1) Make sure you procure both
Sins of a Solar Empire and Entrenchment or SoaSE: Trinity that is patched to
the latest version.

2) Select the version you currently have. There's currently a schism between Steam and Trinity
purchasers (1.055) and non-trinity Impulse/Gamestop supported customers (1.053).

3) Run it, it should
automatically install to your Entrenchment mod directory.

4) Start Entrenchment and
navigate to your options menu.

5) Enable “Sins of the
Prophets”/“sotp”

6) ????

7) Profit! Play the mod.

Trouble-shooting:

“The mod isn't appearing in my
options menu!”

Make sure the mod is in the
correct folder or that you're running the correct version of Sins. If need be,
navigate to the folder manually in Windows Explore in your AppData folder to
check.

“This mod crashes a lot/particle
effects are missing. It sucks.”

No, your cheap-ass Walmart
computer sucks. Sins of the Prophets is slightly more resource intensive than
vanilla SoaSE and will likely result in memory leaks if you're running it at a
level your computer isn't able to handle.

“Random Multiplayer Mismatch
error, etc etc”