Engine runs, blades will engage but mower won't move; and brake is off :)
I've just finished my mowing and cleaned it up with the hose.
What did I do to it?

Hi,
Could have gotten something wet. You will be able to look in at the transmission input pulley at the right rear wheel/tire to see if the belt is on it and it spins by having someone sit on the machine with the engine running and the brake off. If everything spins, and the trans rod is engaged, then it should move.
Peace,
Clarke