Start out with what you learned in class, but don't be afraid to adapt and throw what you learned out and make up new things. Especially if your trainer does something and you find it useful.
I used to do SAMPLE/OPQRST on everyone. Now I've gone almost completely away from it and just ask questions based on my clinical impression. I'm sure I still cover everything in SAMPLE/OPQRST that's relevant, I just don't go in that order anymore and found a flow that is a lot smoother.
Generally, I go:
So what's going on today? (gives me CC, sometimes some history)
When did this all start? (gives me timeframe)
Explain what's happened so far. (gives me the course, other associated signs/symptoms)
Do you have any medical conditions I need to be aware of? (gives me PMHx)
From those 4 questions, you can get everything you need about the situation with follow up questions. Obviously to get a complete med history, you'll still need to specifically ask about allergies and meds and such, but those 4 questions, and their derivatives, can get you pretty far!
Good luck this week!