You'll be able to choose your class. Character generation will be pretty much per Appendix P in the DMG. Abilities will be 4d6, drop lowest and arrange or take a default array.
Applications will only need name, race, class, alignment, deity, and background. You'll begin in Greyhawk City with no cash, but anywhere in the Flanaess will work for origin. Just come up with a reason you are broke in Greyhawk.
If you don't have the rules, OSRIC or Labyrinth Lord AE will give you a good idea of how the game works.