The Software Update page should now show you an 'Update Requested' message, followed by an estimate of how long the iOS 17 download will take (this is typically around 15 minutes). Once you're happy with those, tap 'Agree' in the bottom right-hand corner. This will prompt you to enter your iPhone passcode (the same as the one you use to unlock the phone), followed by a list of Terms and Conditions. On the iOS 17 install page above, tap 'Download and Install'.
