Can someon walk me througth the process?

OK, first, download the dat editor.

 

Then, click open and scroll to C:\Program Files\Lucasarts\Star Wars: Empire at War\Gamedata\Data\Text folder ( or whever you installed the game.)

 

Choose the mastertextfile_*language*.dat

 

Open it and double click a string to edit it, or click edit up at the top and choose "edit string."  You can add new strings by clicking "insert string" and typing hte name of the text.  Make sure to do this in ALL CAPS. 

 

if you, for example, wanted to add a description of a unit, you would type TEXT_TOOLTIP_*UNITNAME* in the top box, and then the description in the bottom one.  Hope this helps.