How can I use my collections links to get a QR Code for each, to them to a poster x Cust to scan?

I Have the QR Code Generator, but when I add the collection links, it says it is wrong, I Don’t know why, I am still setting my store, is not lunched yet, but I am preparing everything first. How can I do this? and i need to create a poster with the QRs to show my collections when I’m at marketplaces. I want them to be separated, each collection with its own QR.