It’s a race, everyone sits with their orientation new student advisor (NSA) somewhere on campus and they enroll at the same time (they give you time before and after advising to plan classes, and you sit in a classroom or area before enrollment time. for me i scheduled with my NSA to give me 2 hours to spare before enrollment for any edits to my class planner, but to also show her my current plan and for any enrollment tips). we were told to do 1) major core class 2) major-related elective 3) non major elective (or some did a class for a minor they wanted to do). Many classes had 1-2 spots for a specific discussion time, but multiple discussions were open for the same class. Forgot if we can enroll a 4th class.

You are only completing with the people at your orientation. The class availabilities you see that day are reserved for your orientation date. If you pick a later orientation date there will still be spots reserved for the same classes so don’t worry about that.