If you already passed the written test and received your "conditional offer" for employment, than you will probably be interviewed by an operations manger or field supervisor. At least that is how it worked when I was with them in LA.
I am not going to tell you what they asked me, partly because I barley remember and do not want to give false information, and partly because I went into it blind as well. Good luck.
Dress nice, and act professionally, you will be fine.