Welcome to the forum.
Have a look at English Banana. I used a lot of their resources for my adult classes in Spain. There are plenty of ideas there for all levels. For your first lesson with them, though, stick to a stab at general conversation (name, kids, job, house) so you can assess their individual levels. It's quite likely that one of them is slightly better than the other so you need to be careful that the one with the least knowledge doesn't just clam up and let the other one do all the talking!