Visit the Career Center co-op webpage. You’ll find information to guide you through the process for all the things that need to be done (dropping classes, notifying financial aid, etc.).
The summer semester is just like any other semester. You are allowed to take a maximum of 18 credits total. We recommend you take no more than 9 credits per track so that you don’t overload yourself. Even 9 credits in one track is a heavy load – remember that the summer track classes move at twice the speed of the Fall and Spring (and whole summer) semesters.