You will meet with the recruiter who will present a test on all part 91/135 stuff you should know, airspace, min wx requirements, NTSB, duty time limits, etc. Next you get to fly in the EC135 Sim to see if you can fly basic attitudes with IIMC and recovery to an approach. You wont be expected to know any aircraft stuff, just that you can keep the greasy side up. Do OK and you meet with the CP, DO HR for your interview. If sucessful you meet the recruiter again and will get a real lowball offer. Know what you are worth and walk if not happy. If they want you they will chase you down and give you what you asked for.
FYI...If you walk you do not get refunded for your airline ticket etc.