Welcome aboard and have fun with SH3GWX. I would suggest you play SH3 vanilla for several weeks or so to get a feel for the game. Then you will be amazed at the mods and really see what they do.
Do the naval academy in the vanilla game as it is impossible to do in GWX.
You have to have SH3Commander. The game is really incomplete without it. Read the CMDR manual twice before you do anything with it. JScones gets a bit testy if you post a question that is covered in it.
Also, read the JSGME manual; JScones really gets testy if you don't.
Finally read the GWX 3.0 manual. It's only a few pages long
but it is the best game manual ever written.