I looked around and there doesn't appear to be an overall guide anywhere to installing mods, and this seems to be the best place to put it. Often see questions in that regard
Standard Mod Installation
Most mods use one of these methods for installation, unless specifically noted otherwise.
There are two ways you can use a mod:
A) One is to install it to "My Documents\My Games\Civilization 4\CustomAssets"
Files installed here override the game's default files. This method is good to use for a personal mod if you're probably never going to distribute it or play multiplayer.
B) The other is to install it under a "C:\...\Civilization 4\Mods" folder
The mods that come with the game use this method. The mod is not loaded by default unless you tell the game to do so. Instead, it's loaded in-game by going to Advanced -> Load Mod.
This is the best way to have multiplayer compatibility for mods, making it easy for each player to load the mod and play a game together.
You can also use this for your personal mod, simply by creating a "Mod" or "PersonalMod" folder here. To have it load as the game starts up:
1) Load the file "My Documents\My Games\Civilization 4\CustomAssets\CivilizationIV.ini"
2) Search for the text "Mod ="
3) Enter the name of your mod here, such as Mod = PersonalMod
After you install a mod in CustomAssets, or make changes to a mod anywhere, you need to clear the game cache. To do this, click the icon to start the game and hold down SHIFT during the loading sequence.
Merging Mods
If you already have files installed to CustomAssets or under another mod, and wish to merge them with a new mod, this is how you do it:
1) Download a free text-comparer program. A good one to use is
CompareIt!, which I'll be using here.
2) Copy the mod over to your CustomAssets or personal mod folder.
3) If it asks you if you want to overwrite any files, make a note of the file name and location, then click 'No'.
4) Each of the files it asked to overwrite with an "xml" extension you can merge using CompareIt. If no XML files were brought up, you can skip to 15).
5) Open up CompareIt.
6) For the source (first) file, load the file you wish to add to the mod (the first XML file you noted above).
7) For the destination (second) file, load the file already in the mod.
8) The source file is listed on the left, the destination file is listed on the right. Differences between the files are highlighted in green. If you're unfamiliar with how the XML text is organized, check out
this post. You can also find detailed descriptions of most XML entries
here.
9) For each difference, compare the two and see which you want to keep. If it's a new addition, the destination file will generally be blank on the right.
10) To copy a difference over to the destination file, click the double >> arrows on the toolbar.
11) To go to the next difference, click the yellow-green downwards arrow on the toolbar.
12) You can also edit the destination file directly -- both sides are text editors. This might be necessary for some differences.
13) Once you've compared the files and made changes, save the Destination file.
14) Then, open up the next file pair it asked to overwrite, and repeat the process.
