Presentations will take place at a time and place still to be determined. In the past, each group had 20 minutes to speak, this will depend on the final timing for our presentations though -- how many groups we have and how long we have our space for.
Please be sure your mentor knows when you are speaking and is prepared to attend.
Final papers should be in the same format as group proposals. They should be structured appropriately for submission to a conference. You might take guidance from resources such as of scott's talk on "How to Write A UIST Paper" or the Bem reading on how to write up behavioral research. They should include material from your literature survey, results of your study, and so on.
You should aim for something 8 pages or less in length.