When in MSFS and asked to sign in using QR code, after I take a picture of the QR code with my smartphone what do I do?
When you use your iDevice camera app to hover over QR code, you should be prompted with link to Navigraph.com. Touch this and you should be further prompted to sign in on your iDevice. Once you do so Navigraph Charts should open on your MSFS computer.
Alternately you can click on the navigraph.com/code link, where you can enter the Code given on screen.