Seniority question?

I am a new cover driver who is about to make seniority. I was wondering if someone could tell me what new benefits like vacation days and raises I will receive when my 30 days are complete. I started an 17.29 because I was a p/t air driver before, and don't know how much my raise will be if I get one. I also need to know how to join the union since our center is new and we don't have a steward yet. Any help is appreciated.