what is the easiest most reliable way to navigate through big cities such as Montreal

by jason jessup
(Bracebridge ontario canada)

I used a rand mcnally trucker gps to make my pickups and deliveries in Montreal Quebec and ended stuck in the downtown core totally lost and in a mess.

What advice do you have to help me learn more about navigating my way through these big tough cities.

Also, what is the best way to plan my trips better so this doesn't happen again. It is my first ever trip to Montreal and first week ever driving a 18 wheeler.