Welcome aboard!
Basically this forum is the manual.
Read things like the tips and tricks thread an other question threads.
In Stock in order to Crash Dive
you need to be below decks, so once you're down the ladder you can dive and your crew will follow you.
The radio doesn't "exist" in stock, but if you load a UI mod it should be mapped or you can do so manually. Just search for "commands.cfg radio" and you should find the instructions.