Some have inverters for continuous power adjusting, others turn on and off the magnetron.

In any case, all that I have ever used have 2 dials, one for power and one for time (and a button to allow to chain multiple time intervals, each with a different power level). I have always used only these 2 dials and I have never used any other buttons that may exist for preset programs.

For many years I have used microwave ovens only for reheating food. Now I consider that I was stupid and I cook all the food that I eat in a microwave oven, from raw ingredients.

This is much better than by traditional means, because it is much faster and perfectly reproducible. Moreover, cooking in a microwave oven removes the need for continuous or periodic stirring that is required in many traditional cooking methods, because the microwave-cooked food is homogeneous (without lumps etc.) even with no stirring, if the time and power level are chosen correctly.

They switch the magnetron on and off, unless they have inverters I guess. I have seen the two knob ones (and I prefer these) and the fancy ones, which all have cryptic user interfaces and usually no manual next to them.