Your don't. There's never been a beta program in Canada. Also there is no official One UI 3 for the Note 9 that I'm aware of. OS upgrades for Note 9 have already reached EoL. You will continue to have security updates though.
Samsung is a bunch of **bleep** morons for it, they clearly can't pull their head out of their **bleep** and see both the US and Canada are the same but still **bleep** us by saying download this **bleep** members app to become beta then go hahaha wE tO sTuPiD