There isn't a central written manual yet, but there are many resources about the game. Here is a list of things you can/should check:

The Frequently Asked Questions (FAQ)
You should look at the FAQ first.

The Warzone 2100 Resurrection Wiki
Warzone 2100 Resurrection Wiki

Lav_coyote25's big Warzone 2100 Docs Project
Warzone 2100 Docs project by lav_coyote25
(Most things are still for the retail version)

The Warzone 2100 Resurrection Forums
If the upper resources didn't bring you the expected results,
you should ask for it in our community forums.