Transit within 24 Malaysia-Shanghai(PVG)-Toronto

I am Malaysian passport holder,
will be transiting at Shanghai PVG from Kuala Lumpur -Toronto, on 26 October 2018.
Back from Vancouver-Kuala Lumpur transiting at Shanghai PVG too on 10 November 2018.

Both transit layover took 4 hours -5 hours.
What are the procedures to go through?
Shall I apply 24-hour visa in advance? How to do it?

Much appreciated for your advice. Thank you.
Anna Lin