A Google Pixel runs Android as Google ships it, without another manufacturer's interface on top. The menus are therefore named exactly as the guides describe them, and unlike Xiaomi devices no extra permissions are needed.
This video follows the Installation on a Pixel step by step, so you recognise each screen as it appears. Pick up your child's Pixel for this, not your own phone – the app belongs on the device that is going to be limited.
The general Android route is in the Android Installation video and, written out, in the installation guide. If a question remains, see the Android FAQ. All videos are in the video overview.