I suggest you download the National Master Agreement, Western Region Supplement, & Southwest Sort Rider. Start by reading about the probationary period to make seniority. I think it may be a crazy long time where you are. People have complained on here in the past about being shafted about making seniority. Hopefully you'll be OK, as it's still early in the year.
Then read and ask about the bidding process to become a driver. Keep your driving record clean!
Good luck.