Just did this on Sunday ottawa to Montreal to orlando. I was NOT impressed that they put connecting passengers in the customs lines with everyone else! And the walk from our gate to customs was LONG. It's a good hike but yes, you follow the US flags. You do have to go back through security also so dump any liquids you might have acquired on the first leg of your trip. I'd say the whole process took 35 minutes with me and my 18 yr old. PACK A PEN to fill out your declaration card while waiting in the customs line!
One helpful tip IF you have a stroller, you can take the fast lane to the far right of the room (way faster). If you don't have a stroller but you all have Canadian Passports that are good for at least the next 8 months, you ca use new lanes on the far left of the room - machines that you put your passport in, it takes a photo of you and then you go to a sepArate customs officer. We tried but my daughters passport expires in October so it was invalid on the machines.
An hour sounds like enough time provided your initial departure is on time. You'll need to hustle and save bathroom and snack breaks until you get to the US gate!