There are any number of reasons users may want to control when and if a computer and / or it's associated monitors go to sleep to save power, or stay awake to respond to commands or run them.
1. Click Start, and then click the 'Settings' icon (looks like a gear)
2. In the 'Settings' window, click on 'System'
3. In the 'System Settings' window, click on the 'Power and Sleep' tab on the left.
4. In the 'Power and Sleep' pane, set the 'Sleep' pull-down as desired. Note that the 'Screen' sleep is a separate pull-down. If you want to make sure your computer stays awake for remote access, set it to 'Never'.
5. Click the 'x' button in the upper right to close the window.