<p>Tastytofu,
you will be in a group according to your major (or in the TO group) in a room with the computers. You will be given a list of GE (or TO) courses from which to choose, as well as information as to which preliminary/prerequisite courses you need for your major. All the while you will have the guidance and info from the advisors present. You will have certain choices but will need to juggle things around a bit wrt time slots you prefer whether there are conflicts. My D for example couldn’t choose a particular class due to its time conflict with another one.
It’s all pretty well sorted out and really you don’t need to prepare too much in advance other than maybe having an idea of which GE or TO classes you’d prefer. If you do prepare, have some second/third choices.</p>