How to Install Basic Mods Edit
There are two types of files mods usually come in. This should explain how to install both types. However, certain mods have their own specific ways to install them.
ZIP Files Edit
These can simply be extracted and placed in the mod folder in the Supreme Commander directory (ie: Supreme Commander Forged Alliance/mods)
SCD Files Edit
These are probably the easiest to install. All you have to do is place the .scd in the game data folder.