If you have worked for Culver's: what to wear to orientation?

I recently was hired at a new Culver's. I have orientation in a couple of weeks. What do I wear? This is Tucson where it is 110 degrees outside all day. Do I dress in jeans and a t shirt? Or more business casual? like slacks and a nice top? I'm not sure what to wear. I wore slacks and a nice top to my job interview. What should I bring with me?? He asked for my ssn and driver's license so they can make a copy. What are Culver's orientations like?