If you have entrenchment:
1. unpack the file
2. cut the folder "Sot13T v0.95 Planets" or another mod folder and go to:
C:\Users\"your_name"\AppData\Local\Ironclad Games\Sins of a Solar Empire\Mods-Entrenchment v1.041
and paste the folder "Sot13T v0.95 Planets" here.
for me is: C:\Users\ASUS\AppData\Local\Ironclad Games\Sins of a Solar Empire\Mods-Entrenchment v1.041
if you don't see the AppData folder you need to go to folder options and mark: show hidden folders and files (or something like that)
3. Now lunch the game, go to Options -> mods, now chose the Sot13T click on it, next click on enable and next click on apply change, if all go well you should have the mod working.
FYI... the XP directory is C:\Documents and Settings\**your user name**\Local Settings\Application Data\Ironclad Games\Sins of a Solar Empire\Mods-Entrenchment v1.041
For SoSE 1.05 patch:
And here, instruction with image, post 3882