Congrats to you all for getting in!
Pamella, I would suggest you pick your courses using this for now:
http://registrar.mcmaster.ca /calen...nt/pg1741.html
(Go down to Requirements) and also, they should have sent in a package to you regarding the list of courses you need, and every other question you might have. [not sure how long it takes to get to you, but I got mine prior to course registration].
If you need help with anything else, just ask
Once you meet an advisor, you can confirm if everything is good.