You can specify that you are unavailable, either for a specified period of time or until you make yourself available again.
A screen appears, displaying a list of options to select:
To specify that you are unavailable for a predefined period of time, tap one of the options in the Quick select duration section. After this time has elapsed, you are listed as available.
To specify a custom unavailability interval, tap Manual. You remain unavailable until you make yourself available again.
To specify a custom preset, tap one of the options in the Select a custom preset section.
When you have specified an unavailability interval, a red dot is displayed in the top right corner of the Home screen.
If you tap this red dot, Do Not Disturb is removed, and you become available again.