To screen record on an iPhone SE, follow these steps:

1. Go to the Settings app on your iPhone SE.
2. Scroll down and tap on "Control Center."
3. Under "More Controls," find "Screen Recording" and tap the green plus (+) icon to add it to the Control Center.
4. To start recording, swipe up from the bottom of the screen to open the Control Center.
5. Tap the screen recording icon (a circle within a circle). A three-second countdown will begin, and the recording will start.
6. While recording, a red status bar or red indicator will appear at the top of your screen.
7. To stop recording, open the Control Center again and tap the screen recording icon, or tap the red status bar and choose Stop.
8. The recording will be saved automatically to the Photos app.

To record sound along with the screen, press and hold the screen recording icon in the Control Center before starting the recording, then turn on the microphone. This method works for iPhone SE and is essentially the same for other iPhone models that support screen recording.