Importance of Unique QR Code

I installed multiple RING devices of the same model. I mixed up the instruction booklets (thinking they are all the same), which has a unique QR code for that particular device inside the booklet. When I then used the wrong QR code, I could not attach the device to the WIFI. After painfully learning this (2 days trying everything) I have all the booklets labeled and with the receipts in a file cabinet. Save yourself, be careful with the QR code/booklet