OP, Like has been said; don't go in blind... Learn ALL you can about the 135 Regs., prior to showing up; it will help you greatly. Once in training you might find there are some differences, vs the general FARS, these are typically regarding your companies Ops Specs; however it is very easy to learn the differences vs the similarities, so study now. Additionally, by studying now you might discover something that you might have trouble with during training. Better to get a handle on it ahead of time. Make sure you are proficient and comfortable with single pilot IFR [I assume it's an IFR gig] They are going to expect that you know how to fly. Some operators have fairly comprehensive training programs, however it is not necessarily the norm in the bug smasher world of 135. Learn all you can ahead of time. Good luck and be safe.