So my wife arrived in Canada last November and i was accompanying her. This was our experience.
Initially they told us on the plane to fill out one declaration card since we will be living in the same residence. During the customs clearance I was told that was wrong since we have different status'... I am a citizen and she was landing with a PR status. When we cleared the customs part, they told us to go to this room to speak to an immigration office. She was very friendly and pretty much reviewed and completed the COPR paper. Nothing to worry about since they don't really ask too many complicated or any difficult questions. Actually i was asking most of the questions LOL We left to grab our luggage and during the exit, they didn't check any of our belongings. They just told us to exit without going through any further checks. Having said that I had created a very very detailed list of her articles, clothing, other belonging etc. I took a picture of all her valuables such as wedding band, engagement ring, other expensive jewelry's, watches, electronics etc. However, they didn't check any of those lists created. I guess it's up to you how detailed you want it to be. Just enough for them not to question further. The documents, like diploma, work reference is not necessary during landing, however I'm sure you will need it when you are looking for a job or want to go to school. Try to get as much notarized and translated documentation ready in case it's required down the road during further education or employment.
Everyone's situation is different but I think in general they are very nice and welcoming.
Oh one more thing if your flight is on a weekday, try to get the SIN number at the airport as well. Just ask the immigration office where to do it. It'll save some time later on where you have go to a Service Canada office to complete that task. It's quick. 15 minutes max. they don't give you a card anymore, so it's just a piece of paper with a number on it. That's it.
I think I've covered all important events, if you have any questions, just ask.