To schedule a computer power-down after some time of inactivity, use these steps:

• Open Settings.
• Click on System.
• Click the Power & Battery page from the left side.
• Power and battery settings

• Click the "Screen and sleep" (or "Screen, sleep, & hibernate timeouts") setting under the "Power" section.

• Choose how long the device must wait before going into sleep mode.
• Set the time to sleep computer

Once you complete the steps, the computer will go into the sleep mode of inactivity you specified in the settings.