In late August until September and again in January you have to go "pick up" your OSAP which is basically you going to a designated location at McMaster and signing off on your OSAP. If you have already paid McMaster in full then you have to take banking information or a void cheque so they can deposit it in your bank account. If not, then you can designate it to go to the school.
You get 60% in September and 40% in January. You will most likely get an email about this whole procedure soon.
Hope that helps