A player in Canada plays depending on where he lives (or born ?). So, let,s use me. I was born and live in Ontario, so I'd play for a team in the OHL. If I were born and lived in Montréal, i'd play for a team in the Q
European players are drafted to the CHL, OHL, whichever in the Import draft. They can choose to come over, or stay in Europe. If they do come over, they play for the junior team that drafted them.
Once they're eligible, they're automatically "in" the NHL draft. If a team picks that player, say Montréal picks me. Then they own my rights and I can only sign with them (in the NHL, I can choose to go play in Sweden, or Russia) If I want to play in the NHL, but not with Montréal, I can ask to be traded (which looks bad on me), or do what Blake Wheeler did and wait until a certain period is up and then become a FA.
The time period is different. I believe for the NCAA it's 3 years for a team to sign the player, before the team loses the rights to him and he goes abck into the draft, or can be an FA.
For OHL, WHL, Q, leagues like that, I believe it's 2 years.
I'm tired right now and could have messed up somewhere really bad, but correct, or close to it as I think.