When do you have to be on campus to move into residence (aka when do you first have to be there)?
And when do all of the first week activities begin?
I have been looking everywhere for first-year information but cannot seem to find any.

Pleaseee Help!

http://fye.mcmaster.ca/orprwelcomeweek.html

Most of the dates have not been finalized yet, and it also depends on which residence you get. Some residences move in on the Saturday and some move in on Sunday.

They'll let you know when all the events are and what your move in day is during the summer

You do not have to move in on the specified move-in day. I personally moved in a day late (I worked at a camp and was still working on the day I was supposed to move in). You can't move in early, but late is allowed. You just need to inform housing services if you're moving in significantly late (like a week-ish, i think)...they'll let you know exactly