For a character's history, you may start simple. Describe where it was they grew up, what sort of family they came from, perhaps cite formulative events that determined certain traits in their personality. It varies from one to another as how complex you may make it.
And to clarify, I think Year is the equivilant of birthdate. By Arin's, 1992, I'm guessing that makes him a third generation Dauntless.
RP Status: available, for time-delayed topics/replies (1.11.12)