So basically they are asking you to make a model boat out of a 10-cm square piece of foil, according to what it says in the book you have read.
Then just follow the instructions they give to you, like so:
1. Test your model boat in a tank of water to see how many pennies it can support before sinking.
Then, after you do that (theres no need to record a video or take a picture thats up to you) all you have to do is:
Talk about how the model of your boat could be improved, or made better to one of your classmates (but post it on the discussion board)