. My App Store icon has gone missing. How can I add apps to my Apple TV

See Identify your Apple TV model - Apple Support. The App Store for Apple TV was introduced with tvOS on Apple TV 4. Ton ATV3 the settings app should allow you to control which channels are displayed.

tt2

Apple TV doesn't feature an App Store. That is a feature of Apple TV 4 & 4K.

tt2

Apple TV 3 doesn't... 😊

tt2

Did they take it away? It used to have it.

The apps or channels are built in to Apple TV 3 and cannot be extended on demand, although Apple may change those that are available from time to time. Apple TV 4/4K have a proper app store where additional apps can be obtained and loaded onto the device from the Apple TV version of the App Store.

tt2