History pgce lesson plan?

I'm doing work experience before I apply for my pgce in secondary history, and tomorrow I have to teach about 20 mins of a year 7 lesson about the Roman baths. So far all I have is a presentation and a diagram of the baths for them to label and put info about all the parts on, do you have any suggestions about what else I could do or how I could make things more interesting? It's top set year 7