First of all, you need to make an SSH connection to your server. If you are not sure how to connect to a Linux server, you can access our article by clicking the link here.
After you have made an SSH connection to your server;
To restart the server: reboot
To Shut Down the Server: shutdown
To shut down the server at a specific time (Example: 21.32): shutdown - 21:32
To shut down the server after a specified minute (Example: after 3 minutes): shutdown -h +3
To restart the server after the specified minutes (Example: after 17 minutes): shutdown -r +17