Great, now that I am more familiar with Photoshop's interface, I'm ready to get to work. I'll start with something easy. I know I'll have to place Ms. Paige's picture on the poster. She's the teacher in charge of the trip.
She sent me a picture, but I'll need to crop, resize and resample it.
I don't know how to do that. This page contains videos that will certainly help me: