how?

From following the link at the bottom of the page to the official site:

Requiem v2.3 full release
Download links:

1. This version should work with your existing v2.x Requiem save games
2. Copy this full release ZIP to your Mods-Entrenchment v1.03 folder
3. Before extracting this ZIP file you can delete any existing Requiem directories in your mod folder.
4. UnZIP it there.
5. You can verify the installation by checking your checksum has been updated to 31433096
   

To elaborate on some of those, though:

You can find out where your Mods folder is by launching the game, going into Optioins > Mods and then Show Mod Path. It varies slightly depending on your OS (Windows XP or Vista).

Make sure you have "Show hidden files and folders" enabled in Windows Explorer (Tools > Options > View tab > select "Show hidden files and folders") because the mod path is usually hidden.

Then just download that file, put it into the Mods-Entrenchment v1.03 folder and double click it to open it up. Inside yuo'll see the actual mod folder. Select it and then there should be an "Extract" button.

Once you do that, just start up your game and go back into Options > Mods and it should show up. Select it there and hit Enable and then it will give you the Checksum number that you can use to compare with the number given above to make sure nothing is missing.

i cant seems to find the MOD folder in my options, and im using firefox, any idea on how to get the hdden folders accessable through firefox

go to control panel, folder options, then click on show hidden folders and click apply.then you should be able to see the folder you are looking for. Now depending on whether you are XP or Vista the paths to find the mod folder are different.to find the path you need start entrenchment go to options ,click on mods and then click on "show mod path".This is the path you will need to find the right mod folder.

i belive my computer is vista (it has the vista sticker...) i got the hidden files, but where do i go for the options, when i do it in the game i see nothing on MODs   (thanks for all the help so far)

In the lower right corner on the game's main menu, what does the version number read?

for Vista, click on the windows symbol lower left hand corner, then click on your name, click on AppData, then local, then IronClad Games, then Sins of a solar empire, then Mods-Entrenchment v1.03 ... this is where the mod goes. (make sure that its not in the zipped folder when you place it here.)    what you can do is double left click on the zipped Requiem folder, inside is another Requiem folder, right click on that one and hit copy.  then go back and follow the path ,when you get inside the Mods-Entrenchment v1.03 right click and hit paste .

when you get that done, start up the entrenchment game. then click on options ,on this screen lower left hand corner click on the button "mods". then you should see requiem listed on the left. click on requiem and then press enable mod, then press apply in the lower right hand corner. after the mod loads go back to the main menu and your playing REQUIEM!!!!!!

thanks for all your help guys