He really should've told near the end. Anyway, I assume you press the power button, because that is the established standard for microwaves in the last 10 years

He really should've told near the end. Anyway, I assume you press the power button, because that is the established standard for microwaves in the last 10 years or so. Probably there might be a timeout and then it starts automatically. This is indeed something you have to learn though, first time I encountered this kind of microwave it baffled me as well.