I'm interested in getting a job here at Mac during the summer working in the labs and such, I have been told that OscarPlus is the place to look but when I go to the site, login and search job posting, I was confused.

There were lots of posting from so many locations not at McMaster University at all, so I'm just wondering how this works and if anyone can help guide me through with this search.

Most of the lab jobs on OSCARPlus are through McWork or whatever it's called, so if you aren't eligible then you can't apply.
I don't think those jobs are out yet though.

Anyways, you're probably better off emailing profs directly.