to bed at 8 during school, you’d start the first night at 8:45, the next at 8:30, and so on). this way it’s less of a shock and they’re less likely to put up a huge fuss.
once you have a set time and are working on getting back to that set time before school actually begins, it’s good to create a night time routine. about an hour before lights’ out, get things done like laying out clothes for the next day, taking showers/baths, brushing teeth, and putting on pjs. if you do the same thing each night before bed, the routine will start becoming a cue that it’s almost time 