Configure Automatic Updates on Server

Start
Control Panel
Search Group Policy
Edit Group Plicy
Expand Local Computer Policy
Expand Computer Configuration
Expand Administrative Templates
Expand Windows Componets
Select Windows Update

Edit "Configure Automatic Updates"
Enable the policy
Use Option #4 - Auto download and schedule the install
Deselect "Install during automatic maintenance"
Set "6 - Every Friday" for the scheduled install day
set "23:00" for the scheduled install time
Use the Always automatically restart at the scheduled time policy"

Enable the policy
Configure the time to the desired value (default is 15 minutes)