You can set up your HomePod, Apple TV 4K, Apple TV (4th generation), or iPad as a home hub to automate and remotely control your HomeKit accessories from your iOS device.
- The device that you set up as a home hub must remain in your home, connected to your home Wi-Fi network, and powered on. Here’s how to set up an Apple TV:
- On your iOS device or Mac, set up two-factor authentication for your Apple ID. Then go to iCloud and make sure that you have iCloud Keychain turned on.
- On your Apple TV, go to Settings > Accounts and make sure that you're signed in to iCloud with the same Apple ID as your iOS device.
After you sign in to iCloud, your Apple TV automatically sets itself up as a home hub. To check the status of your home hub, go to Settings > Accounts > iCloud and look under HomeKit to see if your home hub is connected. Learn what to do if you don’t see HomeKit.
(This how-to is based on my experiences and info on Apple's support pages — where the images sometimes come from.)