You won't need any documents or licenses or anything to have an airsoft gun. Measures should of course be taken to conceal the AEG (gun case/bag, etc) of course. It is not illegal to own an AEG, but it is not legal to walk down the street with it in your hands.
Most airsoft games are organized by players, who either own their own land, or rent land or paintball fields. There's Games and Events Schedule forum, where hosts advetise their games.
Similarly, there are team forums.
Like everyone said, don't try and import your guns. You can bring everything but the gun itself though. Once you're in Canada, don't try and buy from outside of Canada either - import laws have changed a bit, but it's still not worth the "risk" and additional costs.