so it’s brand newCheck the fan protection, it's the most common source of vibration.
Or could be the compressor, that's not a quick problem to fix.
Also check the mounting on the wall, maybe the dampers are too hard or even gone...
Good luck
I just bought some gym mats jigsaw ones 4 stacked under unit dosnt helpPlacing it on 2 inches of hard foam insulation may do the trick.
Tristar from bnqwhat brand ac