You can do a lot on the external display.
If your phone is locked:
Touch an icon to peek at the notification. Then:

If your phone is unlocked:
Twist the phone twice quickly to open the camera.
To learn about camera features, read the Camera app's help.

This is a curated group of apps that work well on a smaller screen. Other apps may not display as expected.
To allow app shortcuts for any installed app:
Touch Manage apps > See more.
You can now add shortcuts for any installed app.

Adjust shortcuts:

To access the media player:
| Task | Gesture to use |
|---|---|
| Answer call | Flip phone open |
| End call | Flip phone closed |
| Make call | You can use Google Assistant, or swipe left twice to access the dialer or your contact shortcuts. |
| See more options during call | Tap the display |
You can change how your phone handles calls when you flip it open/closed.
If you reject a call, you can send a quick text message from the external display.