If you want to join other user Home Sharing accounts to control their devices, you need to be invited first. Please refer to the article below to see how to be invited.
Once you have received your invitation message, please use the following steps to join:
1. Navigate to the Home Management page
2. Tap on the Join Home button
3. Enter the invitation code and you should be good to go!
When you successfully join other user Home Sharing accounts, you can switch to their homes in the Shared Home column.
You'll now be able to access and control their devices.