When you scan the TrueLayer QR code, your phone will open a link in its browser and will then open your mobile banking app. You will see the following screen on your desktop whilst this opens:
After authorising the payment in your mobile banking app, you will be sent bank to a TrueLayer page indicating whether the payment completed:
After this, your desktop journey will continue and you will be redirected back to the website that you started the payment from.
Check out a demo video of a payment using QR codes in action: