The Mini is designed to run 24/7 so there’s no feature to turn it on/off by schedule. However, you can schedule your content to play at specific days and times by using the scheduling tool in the Windows version of XOGO Manager: https://www.xogo.io/digitalsignageblog/2019/12/2/xogo-advanced-scheduling-feature

You can also reboot your Mini remotely by clicking on your player in the Players section then going to Advanced at the bottom of the screen. 

If you want to schedule your Mini, TV and/or other items to turn on and off automatically -for instance to conserve electricity- you may want to consider an internet-connected power strip like this one that will turn your devices off at certain times of day: https://www.ubnt.com/mfi/mpower/