1. Quick Peek
When you scroll over one of your top 6 apps in the navigation menu of the new Fire TV interface, the bottom portion of the screen will, when possible, display movies, shows, and channels that are available within the highlighted app. The content is presented in one or more labeled rows that look and act like the various rows on the Fire TV Home screen. This app peek area isn’t actually part of the app’s interface, but rather, it’s just using the Fire TV’s interface to show you content available in the app.
When the app peek rows are being displayed, you can press down to navigate within the peeked content. Just like the rows in the Fire TV Home screen, these rows will scroll horizontally for quite a while to list more content options. Pausing on one of the items will sometimes display a video preview of the content in the upper right, where a screenshot of the content is usually displayed.
2. Change Profiles
The new Fire TV interface provides a number of ways to add a new Fire TV profile:
1. From the start-up screen after turning on your Fire TV Stick
2. From the center navigation menu, Profiles (icon on far left)
3. From Settings (gear icon on far right) > Account & Profile Settings > Profiles
4. By saying “Profiles” after pressing the voice button on the remote
3. Open Developer tools menu
You can use your voice and just say “Open Developer tools menu”

Change Screensaver / Sleep Timeout
Watch the apps in action here: