The Examinations Committee must approve your program consisting of the mandatory courses and your choice of the electives (possibly including an internship). In order to obtain this approval you construct a program, possibly with the help of your mentor and study advisor, fill out the program form, sign it, get it approved by the master thesis supervisor of your choice (or another representative of the same research group in CS or EE) and hand it in at the student administration office (MF 5.103). See the graduation checklist for a timeline and the required forms. To make sure you do not miss courses you should choose it is recommended to submit your study program around the start of quarter 3 of your first year. If needed you can still make changes later and reapply for approval.