Post your questions on fleet creation here.  We'll help you figure it all out.

I'm still a little fuzzy on crew. If I purchased a Crew-4 system this would be Main crew, does this include everything I need to fly a ship? Are the special crew types separate purchased systems?

Every ship has "Crew(Main)-0" by default, which is enough to fly the ship, and grants 1 action per (Day or Combat) turn.

A Crew(Main) greater than 0 adds additional actions, so a Crew(Main)-3 would get 4 actions.  The number of actions you want depends on how many things you want to do during a turn.  If you have 5 weapons systems, you probably want at least 5 actions.

Special crew types are separate systems.
This message was last edited by the GM at 01:40, Sun 03 June 2012.

And buying Crew(Science)-2 without any additional crew(main) would not grant me extra actions?

Also, what are engineering actions? Just jury rig and repair?
This message was last edited by the player at 01:45, Sun 03 June 2012.

Yes and no - Science crew grants additional science actions (see that section).

Those are the only Engineering actions right now;  that's why Engineers are included in the main crew.