Fotini, I think this first activity, even if it was my idea, is a bit too complicated. I've been thinking of something similar but easier. What about if we write something like:

You are now going to see a picture of the students from Badalona. You can see their names if you click on them. They are going to write their presentations immediately after. They are not going to tell us their names. They are only going to give us their description and where they are in the picture. You have to guess who they are and match the description with a student in the picture. Once you think you know who he or she is tell him or her in the comments.

What do you think?