Apple's Remote app lets you control the Apple TV with your iPhone or iPad over Wi-Fi. Not only does that give you a backup if you ever lose the aluminum hardware remote that comes with the Apple TV, but it also lets you maintain control even if you're not in line-of-sight, makes navigating large amounts of content — including Home Sharing libraries — easier, and thanks to the virtual keyboard, makes search term and password entry a breeze. Here's how it works!
If you don't already have the Remote app installed on your iPhone or iPad, you can download it for free in the App Store.
After you've got the Remote app installed, the next step is to make sure that Home Sharing is enabled on both your Apple TV and your iPhone or iPad. You'll only need to do this once and if you've already turned it on previously, you can skip the next two sections. Also make sure that your Apple TV and iPhone or iPad are on the same wireless network.
That's it. Your Apple TV should now show up in the Remote app on your iPhone or iPad.
In order to navigate around the screen, just swipe your finger in the larger empty area either left and right or up and down. Once you've got the item you want highlighted, just tap on the screen. Anytime there is an option to enter text, you should either see a text input button pop up or the keyboard automatically launches itself.
You can also access any music you've purchased from iTunes through the Remote app and stream it to your Apple TV via iTunes in the Cloud. To do this just tap Done to exit the control portion of the screen. From here you can choose to browse playlists and more. Anything you play through the Remote app will automatically stream right to your Apple TV.
The Remote app is super simple to use and a lot more convenient than the small silver remote that comes with the Apple TV. I've also found it to have a much better range which makes it great for use when you're in another room and want to pause music.
As a side note, I've also seen issues with guest networks. For example, if you're Apple TV isn't showing up, make sure your iPhone isn't on a guest network while your Apple TV is on the main one. This seemed to be a non-issue in the past but has presented issues with some people with the updated version of the remote app.
If you need any additional help or have specific questions check out our Apple TV Forum!