I had to send copies of my passport page and endorsements (US citizen) along with a completed Annex A (found at the end of their email-- I had to do some creative highlighting/pasting/printing to get it on to one page, lol). I also sent two PR photos that I had taken at a Shoppers Drug Mart while I was in Canada this past summer. I had both of the photos attested on the back, but realized later that I only needed one of them to be attested. No harm done.
I made the mistake of sending it by USPS first class registered mail and it took forever to arrive. Once it was actually received in Ottawa, though, it was just a few days (I think 5 days, but 2 of those were a weekend) before they approved my application online, and then they initiated the return delivery with my CoPR on the following day. They returned the copy of my passport bio page to me along with two copies of my CoPR, one of which has one of my PR photos attached, and a sheet explaining what the CoPR is and what my responsibilities are.
My CoPR is dated as expiring June 9th, 2019 (1 year and 1 week from the date I took my medical... I suspect the 9th is the day they uploaded the results, but can't confirm), so I have a lot of time to land. I've arranged for my next visit to Canada to be in February, so I'll complete my landing formalities at that time. Realistically, there isn't a lot between now and landing-- I'm putting together my list of goods, but that's about it! There are a couple threads around about landing experiences, so I'd look to those for post-PPR stuff (that's where I'm looking, too).