When you apply for Foundation (or degree courses) you need a portfolio of your work. You need to present this in the best possible order to manage the experience of someone looking at it. It's a good idea to get some advice on that presentation and the running order of your work.
Once you get accepted for Foundation, they will give you starter assignments to keep you working over the summer. Here is a sketchbook that shows one student's responses to their assignments. The brief is always open-ended and vague. The idea is to get you making images and working on something, not to provide you with a specific steer to a specific, detailed outcome.