First of all congratuations for receieving your immigration visa. Pleased be advised that you have to make your landing before the expiry date of the visa. More over you have to know that this visa is just to allow you to inter Canada and become a PR BUT you must have the PR card which will be sent to the canadian address (address of your relatives or fraiends in canada where you will stay for the first days) which you must give to the immigration officer during the processing of your entry at the point of entry (airport for example). One important thing you have to remember is that you have to keep the proof of landing paper which you will receiev after finishing the landing procedure (usually the officer will staple it to your passport), this is an important document whih you have to keep it in good form (and the PR card as well) untill the citizenship final stage.
Have a good future in Canada !!