how to trigger a scenario twice a day (7 a.m. / 8 p.m.) ?
Thank You so much 
You can start whenever you like.
Use the advanced settings in the schedule.
Use the start and end times and add the interval. In your case, Start at o7:oo, set the Interval to 780 min. (13×60 min) and the end time after the last run is done. Maybe 20:10
You can further choose if it should run every day or just on specific day’s, like Mo- Fr.
