A schedule restarts the server at a fixed time. Valheim doesn't read commands sent by a schedule: no message to the players, and no save command needed, the world is saved when the server stops.
GamePanelSystemSchedulesCreate, pick Blank Schedule, Continue, then the name, frequency and time, and Create Schedule.
On the schedule page, Create Task: Send power action, Restart the server, offset 0.
Trigger runs it right away to try it, restart included.
Common errors
- Pick a time when nobody plays: connected players are disconnected without warning.