[XP]Boulder Onto Switch

In the first dungeon of my game, i have the slightly-cliche "push this thing onto this switch to get this result" puzzle. only problem is when you push the boulder to the switch it doesnt go on top of it. So my question is how would you make it so that the boulder goes on top of the switch and then is set there and can no longer be moved?

Make the switch its being pushed onto "through" if it isn't, and the n also the switch that the boulder turns on (the one that opens the door) use that to turn on a page in the boulder event that just makes it do nothing.