How/where at the store do you get the money back? Is it at the cashier?
And then are we supposed to save the receipts and claim them in Switzerland for taxation?

How much is the VAT? Is it a major saving?

However this is still at the stage of being a draft of a law. It has not been enacted and if it is, it will not start before 1.1.20. So purchases under €50,-- are still eligible for the refund until something actually changes legally and at least until the end of this year.

Kaufland in Lorrach handles tax return very easily. It's one of the bigger grocery shops. They have their own tax return forms that you can ask the teller while paying. Just write you name and address and get it stamped at the border. Next time you go back to the shop and get your refund deducted from you new bill.

Or it can be paid out in cash if you are not buying anything that time, even if you originally paid by card.