Get a lox and bagel from St Viateur Bagel. Probably my favorite snack on earth.
Go to the top Of Mount Royal and and enjoy the views. If you're healthy/fit, hike up it. It's great.
My wife and I have done two guided group bicycle city tours for an afternoon around the city with these guys.
https://fitzmontreal.com/
It's so much fun, we highly, highly recommend it. You meet other people and see all the fun sports in Montreal. You don't have to be very fit at all.
I also recommend spending a morning or afternoon walking around old Montreal. They have great restaurants. We went to this Italian restaurant for a nice dinner one night. It was great.
https://ristorantequattro.com/
Walk around St Catherin's street. It's great.
We stayed at this hotel one block off St Catherine's street. It was a a really good hotel in a great, walkable location for a great price. I would book there again.
https://www.marriott.com/en-us/hotel...town/overview/
Enjoy your trip. I really like that city.