From TheWarWiki

Getting addons

First, it is up to you to select the addons you want to install. A major source currently is Curse. The Curse Staff check each submitted addon to ensure that it contains no malware. Addons consist of plain text files and graphics; they have no executeables in them so they cannot contain viruses or keyloggers. If for some reason an addon package you download contains an executable, don't run it unless it's from a truly trusted source.

Alternatively, there is the Curse Client which allows you to install addons and keep them up to date automaticaly. If you use the Curse Client you can skip most of the following steps.

Installation

To install a addon is quite simple. Addons on Curse are mostly packed in a .zip archive. If your OS does not have a built in tool for decompressing those archives you need first to get one: there are dozens of freeware tools available on the internet such as FilZIP or 7zip.

Now open the directory where you need to put the addon in. In the root of your Warhammer installation folder there should be a folder named Interface. In this subfolder you find another folder named AddOns. This is the place where we need to put the extracted addon folders in. The path looks something like this:

• WarHammer\
  • Interface\
    • AddOns\
      • CleanUnitFrames\
      • CurseProfiler\
      • LibSlash\
      • LibTimer\
      • SelfTarget\

In the above example I already have several addons installed: CleanUnitFrames, CurseProfiler, LibSlash, LibTimer and SelfTarget. As you can see each addon is put in its own subfolder in the addon folder. If you go inside a addon folder, you find a file named like the addon folder but with the extension .mod - if this file is missing, the addon won't load and something is wrong.

That's it. You now can run your Warhammer game client and the addons should automaticaly appear. There is no need to first activate them. To check if addons loaded as they should you could use the following in-game command which brings up a window with information about the detected addons:

/script WindowSetShowing("UiModWindow", true)

Problems?

If a addon you installed is not running, first try to install another addon (to see if the problem is specific to the addon itself). If it seems that other addons are not running either, continue to read. If it is only one addon having problems, try seeing if the addon has a "readme" file for more info, or check the page from which you downloaded that addon.

General things...

• Be sure you're placing addons in the correct path described above. There is a \User\Interface folder in your WAR directory, but that's the wrong place!
• In rare situations, mostly with the Closed Beta Client, it helped to select "Check all Files" in the War Launcher.
• Check the settings path: in your Warhammer\User\' Directory there should be a file called UserSettings.xml - open it with a text editor and search for AddOns path=. This should look like: <AddOns path="Interface/AddOns" /> (if it doesn't, you may need to place your addons in a different folder as specified there, or change it to match).
• If you start Warhammer with a shortcut from your desktop, make sure the Target directory in the shortcut's properties (right-click on the shortcut, then choose Properties) matches the location of the WAR install that you're placing the addons in.

If there is no Interface directory in the base WAR folder...

• Just create it, and create the AddOns folder inside it. Don't try to create an addons folder inside \User\Interface\ - that's the wrong place.

Still not working? Try asking for further help in the WHA UI forum.