ThalesPo wrote:stuck on the level 3
Welcome to the forum!

Make sure the skeleton falls onto the raise button.
Then, go to the room right of that room, towards the gate in the middle.
At the top of that room, shortly go back into the room with the skeleton - the gate will fully open again - and then trigger the raise button after the gate.
That raise button will open the gate on the lower right, towards the room with the level end door.
If it's still unclear, you could open the mod in
Pr1SnesLevEd, to study level 3.