If your using Windows XP (then your sane), follow these steps:

1: go to C:\ directory and find a folder called documents and settings

2: right click the folder it and select search option

3: Search for Ironclad. You'll find two folders as a result, the one you want is looks like: "C:\Documents and Settings\Tom\Local Settings\Application Data\Ironclad Games"

4: Open the Local Settings one and navigate through the SOASE folder until you find a
folder called mods.

Once you have downloaded the mod, follow these steps (make sure you have patch
official patch 1.02 or newer, 1.05 is newest so far, to enable mods):

1: make a new folder in the mods directory in the name of "your mod".

2: Copy the contents of "your mod" into your new folder.

3: Load up Sins of a Solar Empire

4: Go to the options button, and you'll see a new button called mods. Click it.

5: You'll see a list with "your mod" folder in it. Select it, and click "activate mod"

From this point, some mods that require alot of data memory to run, like the newest
Seven Deadly Sins mod, you'll have to click start mod on load check, exit the game,
and start it again. It really depends on the mod itself. Its best to just read the
readme that comes with the mod.