Try Haven
This is Haven itself, running in your browser with made-up things in it. Choose some answers about the person who'll use it, and Haven sets itself up the way it does on a real computer. Then press anything.
Carers: hold Home for 3 seconds, then use the demo PIN 1234. Websites open in a new tab here; on Haven they open inside it, with the Haven bar. Nothing you do is sent anywhere, and it's all forgotten when you close this tab.
Why Haven set it up this way
Every part can be switched on or off later, and a quiet or sick day lasts only for that day. The person's favourite things go on shelves of their own, which aren't shown here.