See: https://forum.magicmirror.builders/topic/11065/using-smartthings-motion-sensor-to-turn-on-off-monitor

My best bit of advice is always look for an easy starting point and don’t reinvent the wheel if you don’t have to… Some possible inspiration… https://ourcodeworld.com/articles/read/55/top-5-best-jquery-scheduler-and-events-calendar-for-web-applications