TLDR: The guide explains how to scan the photo page in your passport by holding your phone horizontally 20-30 cm away to align with the on-screen box. During scanning, a green box and progress bar appear. After scanning, review the photo and submit it. Next, you'll be prompted to scan the passport's signature page.
Scanning your passport photo page
After confirming you have a passport, you'll be asked to scan the photo page in your passport. You'll see an animation on the screen for how to hold your device and your passport. Press 'Start scanning' and your camera will then open to photograph the passport.
The photo page is the shiny page showing your photo, name, place of birth and other details.
Hold your phone horizontally to match the passport. Hold the phone 20-30 cm away from the passport, so that the box on the screen lines up with the photo page. Ensure all four corners of the photo page are visible in the grey box you see on the screen.
When the scan is in progress, you will see a green box appear around your ID. You'll see a progress bar on screen whilst the scan completes.
After the scan is complete, you'll see the photo that has been taken on screen and can then submit this.
Next you will be asked to scan the signature page in your passport. You can read more about completing that here.