You've joined the ship, either as a paid of STARFLEET, International or as a non-paid member of the ship itself.  You've decided you are now interested in creating for yourself your own persona.  While there is no one way to create a persona, there is often a few questions one should be able to answer to make things easier on yourself.

1. What race would you like to portray?
2. What was your home life like?
3. If you have decided to become a member of Starfleet, what was your life like at the Academy?
4. What was basic training in the Starfleet Marine Corps like?
5. What does your command history look like?

This is a good basic outline to start a persona.  You can add as much or as little as you want, but this will give you a great start.