Read the article. If you are willing to do the paperwork, most goods are exempt under CUSMA.
The “section 232” tarrifs on steel, aluminum, and vehicles are the biggest problems right now. Those may eventually be ruled illegal anyway (in the US).
Let’s just continue to buy from and trade less with them every chance we get.
At the store it's doable, assuming a fairly permissive definition of "non-American". But, the digital giants are harder. Lemmy-type people can manage an approximation, but non-technical people would struggle. I myself am having trouble with online shopping, as mentioned elsewhere in the thread.
I think Canadians have to suck it up and move their businesses elsewhere. The time of easy trade with the US is over and we need to broaden our trade alliances, and actually take advantage of them.