Some basics for everyone who is in a real hurry:
The XWAU 2025 Installer Manager will no longer overwrite your base X-Wing Alliance installation anymore. It will instead make a copy of it, and then install the mods into that copy.
This will prevent many of the issues we have seen before, like Steam 'repairing' an XWAU installation, breaking everything in the process. It will also make it easier to have multiple mods installed, like the XWAU and the TFTC.
Because of this you will need to prepare a few things before starting the installation of any mod.

1. Install the Star Wars: X-Wing Alliance game.

We support all flavors of the game (GOG, Steam and even the original game) though we strongly recommend the GOG version, as it is the easiest to work with. If you install the original game make sure that you have the v2.02 patch installed as well.
You can install the game anywhere you want, it will require roughly 850MB of space. The XWAU will not modify this installation, but only use it to create the mod-installation.
 
For the purpose of this guide this folder will be referenced as Vanilla directory and we used D:\GOG Galaxy\Games\Star Wars - X-Wing Alliance for this demonstration.

2. Decide where you want your mods to be installed

This can be in most places you want, but we highly suggest to have the mods be installed outside of your Steam or GOG folders. While it should work in most cases, you never know what the game launchers might decide to do with installations they don't know.
We also recommend this to be a folder that is just for your mod installations. So let's say you have a Games on your hard-drive, it would be good to create a subfolder like XWAU-Mods in there.
Make sure you have enough space available here. Currently the XWAU needs about 10.5GB plus another 5.6GB for the installer, but there is still more to come and the TFTC is much larger than this as well.
 
For the purpose of this guide this folder will be referenced as Mod directory and we used D:\Games\XWAU-Mods for this demonstration.

3. Deal with any anti-virus solution you have running

Now, we fully understand the importance of anti-virus solutions for your PC. Unfortunately due to the way the XWAU is working, most AV solutions will flag the mod as a malicious program. Sometimes you will get an alert allowing you to let it run anyways, but often the AV solution will simply block or even delete the mod or parts of it.
This can lead to many issues. You might not be able to download the mod, installation might be blocked, and it might not run at all, you might get unexpected crashes or some features won't work.
Because of this it is best to exclude the Mod directory in your AV-solution.

If you are using Windows Defender you can exclude your Mod directory like this:

1. In your Windows environment, go to Start > Settings > Update & Security >Windows Security > Virus & threat protection.
2. Select Manage settings > Exclusion > Add or remove exclusions.
3. Select Add an exclusion and choose Folder
4. Add your Mod directory

For other solutions please check with the vendor to see how you can exclude a folder.

4. Download and prepare the XWAU InstallerManager

Head over to the Downloads section of the page and download the newest version of the XWAU InstallerManager linked right at the top of the page.
Unpack the downloaded file into a location of your choosing, due to the issue with AV-Solutions we do recommend to place the InstallerManager in a subdirectory of your Mod directory.  
For the purpose of this guide this folder will be referenced as InstallerManager directory and we used D:\Games\XWAU-Mods\XwaInstallerManager for this demonstration.

Okay, the hard part is actually done now, all the preparations you have done are only required once, from now on all installations of new mods or updates of mods will be much easier!

Go to the InstallerManager directory and double click the XwaInstallerManager.exe. If you see a pop-up telling you that the program is unknown and might be unsafe, please select Show more details and then Run anyways
On the first run of the InstallerManager it should prompt you to make a few settings:

Depending on your method of installation the Vanilla directory will already be properly set. If not use the directory button to set it to where you installed the game. Next use the directory button below and set this to your Mod directory.
 
For our example it should look like this when done:

You can also create a desktop-shortcut to the InstallerManager here for easy access if you wish.
Click on Save settings to go to the main screen.

Once the settings have been done the mod list in the InstallerManager should populate and look something like this:

Here you will find a list of all available mods and their add-ons. For now we are only really interested in the XWAU2025_Full_1.0.0.zip.
Use the marked download button to start the download. Depending on your internet connection this might take a while.
 
Once the download completes you should see that the install button has now become available:

Use the marked installation button to start the installation process. You should see the following prompt:

 
Unless you want to install the XWAU 2025 is a different folder than the default (which we do not recommend) simply click yes to continue.
The installer will then first create the above folder (in our example the Mod installation folder is D:\Games\XWAU-Mods\XWAU2025), copy the contents of your Vanilla directory into it, and then start the installation:

 
Click Next, read and agree to the License Agreement:

 
Click Next, read the installation notes:

 
Click Next, select your preferred aspect ratio and the graphics preset:

 
The mod is now ready to install:

 
Click install and let the installer do its thing. Depending on your machine this will take a few minutes, and in rare cases it can appear to hang. So be patient and give it some time.
 
Once installation has been successful you'll see the following screen

 
Click Finish, and then that's it, you have successfully installed the XWAU 2025
You can skip the manual installation instructions below and go right to launching the game

In case the above method fails, you can also manually install any mod. This will be required if the PC you are installing the mods to doesn't have internet access, or your computer security prevents the Installer Manager to access the internet

If for whatever reason the Installer Manager cannot download the installation files you need to manually download them. The packages are listed on the downloads page
Download the mod you want and place the downloaded file into the InstallerPackages folder inside the InstallerManager directory. (If you click on the "open" button in the Installer Manager it will open that directory for you)

We have also added the feature to manually add the required JSON file to the installer in case the InstallerManager cannot download it. This should make the installation easier because you will not need to copy your Vanilla directory manually.
For this to work please download the Configuration JSON and place it in the InstallerPackages folder inside the InstallerManager directory. (It should be called mod-versions.json)
When you click "Check updates" in the InstallerManager now, it should no longer come up with an error but should list the available packages like in the screenshot that linked here. If so you can now proceed with the automatic installation.
 
If after the download of the installation package you still do not see the remaining packages being listed and you only see the downloaded one you have to resume with the instructions below.

Before proceeding you need to manually copy over your Vanilla directory into the location where you want to install the XWAU 2025. Remember that location as you will need to provide it later.

Once the download completes and you placed the file inside the folder, restart the Installer Manager and you should see that the install button has now become available:

Use the marked installation button to start the installation process.
The installation should start immediately:

 
Click Next, read and agree to the License Agreement:

 
Click Next, read the installation notes:

 
Click Next, and provide the folder where you copied your Vanilla directory into:

 
Click Next, the installer will validate that you have chosen a folder with the base installation of the game:

 
Click Next, select your preferred aspect ratio and the graphics preset:

 
The mod is now ready to install:

 
Click install and let the installer do its thing. Depending on your machine this will take a few minutes, and in rare cases it can appear to hang. So be patient and give it some time.
 
Once installation has been successful you'll see the following screen

Click Finish, and then that's it, you have successfully installed the XWAU 2025

Limit the game to 60FPS

Unless you limit the game to run at 60FPS, you will run into issues with the in-game AI as well as heavy stuttering when entering the hangar. Limiting the game to run at 60FPS will solve this issue, please check with in your GPU driver for the best way to achieve this. (Limiting your monitor to 60Hz will often solve this as well)

Launch your game

So, you are about ready to launch the game. Go into the Mod installation folder and launch the Alliance.exe application. We suggest to create a shortcut to it on your desktop, or to pin it to your taskbar so you can start it with one click.

The new launcher should look like this:

 
Should you have an existing pilot from older XWAU installations, or even from the original game you can still use them.
Make sure to place the <PILOTNAME>.plt and the <PILOTNAME>_emails.bin in the UserData/XWAU/Pilot folder inside your Mod installation folder. Then use the Pilot Options... in the launcher to select your pilot.
If you don't have an existing pilot, the game will ask you to create one during the start of the game.

 
More information about the available tools and configurators can be found here