After your study permit is approved in the GCKey portal, you have to submit your passport at the visa application centre for Temporary Resident Visa (TRV) Stamping. This is different, and the Study Permit is different. The TRV is necessary for citizens of certain countries (like Kenya) to enter Canada.
Once you land in Canada, at immigration the Immigration officer will ask you questions, and will print your Study Permit and give it to you.