It turns out that they are intervals of time, by 15 seconds. So pressing 6 means that your food is nuked for 1:30 sec. The interface doesn’t communicate this at all to the user. This microwave starts right away after pressing one of the numbers buttons as well.
The percentage numbers on some of the icons seem to indicate some kind of power setting, but the icons were unusual to me. The buttons with the white triangle in the red circle and the line in the green circle were really bewildering. Through trial and error I found out that to cancel the cooking time, you have to press on the white triangle in the red circle button… twice – once to pause, again to stop. As for the 2x button, I don’t know about that one.