Pretty much you have to do a few courses over a weekend and a bunch of paperwork to apply for a PAL (Possession and Acquisition License). Takes about 1 year to get it in the mail. There are a crazy amount of restrictions on what guns you can buy/own/sell. No full autos and recently no semis or "assault rifles". Those are prohibited.
There are three classes of guns that you CAN own: non-restricted, restricted and antique. Not going to go into the details as they are retarded but here's the wiki page on it:
https://en.wikipedia.org/wiki/Firearms_regulation_in_Canada#Classification_of_firearms
Most of the laws are arbitrary and make absolutely no sense.
Key difference between USA and Canada is that here guns are PURELY used for hunting and sport shooting. So obviously there are no carry permits for regular citizens. If you use your gun for self-defense you are fucked. Even if armed men break into your house and you injure/kill them with a gun, chance are you're going to go to jail. That's Canada for you.