In the end the process was a little more complex than expected, will explain more in case it helps others.

Arrived in CAN, 144 transit sign hard to find. Found it and the area was closed. Picked up form and asked around and was told to wait in a seating area. About 30 mins later someone came and asked me all my plans. Took huge offense to the number of turkey entry stamps in my passport ( I visit 50 countries a work) and seemed on the edge of denying me.

I’d booked a flight with points to leave from CAN to HKG 2 days later but was planning on maybe leaving 4 days later straight to Singapore. But wanted to just get into the country and see

Then placed an 144 hour entry QR code in passport and repeatedly told me . You have to fly from this airport. You must leave from here. Do not go to Hong Kong by land. Do not leave from Shenzhen. It was perfectly polite and relevant but I was as if he’d read my mind as those were things I was considering.

Now I’m a little annoyed as I’m concerned I have to take the flight I showed them when now I’d rather fly within the time marked on my entry visa but another flight ( not to HKG but to a different 3rd country) and one day later. Do you think that would be a problem ?