You set departure times (up to three, for different days of the week). Make sure departure times are selected. Then you select "charge in time slot", instead of "charge immediately".
I use one departure time for weekdays (9 am), and one for weekends (11 am). These two are always active. The third departure time is set for early morning (6 am tomorrow) and usually deactivated. I activate it when I need to go out early to a job site. On weekdays usually I leave before 9 am, so the car is around 90% when I leave.
You can also set it on myBMW app. Again departure time works only if you charge in time slot.