This is a fairly common question, so I thought it deserved a tutorial of some sort. Please bear in mind that any instructions in a mod's thread or on it's download page override these- this is a general tutorial and is not meant to apply universally. (Some things are exceptions to the rules- that's how it works). Q: Where do I install mods? The Program Files directory for Colonization. Where this is depends on your system (and if you have Civilization Complete). The path to this folder for standalone Colonization (not Complete) should resemble: "C:\Program Files\2K Games\Firaxis Games\Sid Meier's Civilization IV Colonization" The first letter obviously depends on what drive you've installed Colonization to. The Program Files might be "Program Files (x86)" if you installed to a 64-bit system. The 2K Games\Firaxis Games\ is the standard folder, but it could be different for you. If you're having trouble finding this, search for "Colonization.exe". The folder containing "Colonization.exe" is what you're looking for. On Windows 7 (and probably Vista too), you can right-click on a shortcut to Colonization on your desktop and select "Open File Location" to get to this folder. Once here, you need to create a Mods directory. Just right-click, select "New -> Folder", and name the new folder "Mods". (There should not be a Mods directory already, unless of course you've already created one). Q: How do I install mods? If the mod in question comes with an executable installer, just run that. If the mod is instead in some kind of archive file (like a .zip, .rar, .7z, etc), you first need to extract the archive. If you can't find a program to extract .rar or .7z files, I highly recommend 7-zip. Once you've extracted the mod, copy the extracted folder to the Mods directory. Make sure that the mod folder contains an "Assets" folder inside it. For instance, you should find that a mod's file structure looks like this: \Mods\YourMod\Assets And not like this (as an example): \Mods\YourMod\YourMod\Assets If it doesn't look like the former, just find the folder with "Assets" in it and copy everything (including Assets) into the first "YourMod" folder. Q: What else do I need to do? For most mods, you will need to install the 1.01f patch for Colonization, available here. Some mods, made before March 2009, will not work with the patch- all made afterwards probably will. If you get errors on loading, please check the date of the mod and check that you installed the patch before reporting them. Q: Can't I just use the in-game updater to install the patch? This is not a good idea. The in-game updating system in Civilization 4 (and, as a result, in Colonization) seems to be broken. If you are having trouble with the patch installer for some reason, try this download instead. Q: Why can't I install mods to My Games? Because people have reported weird issues when installing mods to "C:\Users\[username]\Documents\My Games\Sid Meier's Civilization IV Colonization\MODS" (or whatever that path is on your system). I don't really know why this is the case- all I know is that these weird issues are fixed when the mods are installed to the Program Files directory instead. Therefore, it is not recommended to install mods to this directory. Q: What is the Custom Assets directory for, then? Custom Assets is something you should almost never need to use. To understand why, you first need to understand how mods are loaded. Colonization loads Assets (anything in the Assets folders) in this order: Custom Assets Mod Folder Vanilla Game Files placed in Custom Assets will normally override whatever is in mod folders. This can be useful if you want one mod (like the Blue Marble graphics mod) to override all your other mods. It can cause problems if the Custom Assets and your loaded mod conflict. Usually, a mod can be set up to ignore Custom Assets with a setting in its .ini file. But there are no doubt mods that don't do this, even when they should. Q: How can I install mapscripts and scenarios? They don't have mod folders. Mapscripts and scenarios (.py files and .ColonizationWBSave files) should go in the "PublicMaps" folder inside the Program Files directory for Colonization. I recommend you read this for more information about what exactly makes a map "public"- it is intended for modders though, so you might not fully understand it.