You have to claim your PR status by landing in Canada within a year from getting PR. After which you will receive your PR cards by mail (To a Canadian Address). You will need your PR card if you wish to fly into Canada. The only other alternative is to drive in with just your landing confirmation document.
You have to live in Canada for 2 years out of 5 to keep your PR and 3 out of 5 to be eligible for citizenship.