Here is the scoop: (An electrician was "helping me" and now has disappeared :laughing

Synopsis: 200a service main for house. ran 3, 1/0 al to shop, 120' underground for 125a sub-panel (2 hot, 1 N). Waiting on my 125a breaker to put in house main. I have a 200a panel (for the shop) which has the crossover connection between the neutral bus bar and the equipment ground bus bar. I have 2 8' ground rods. Since I didn't run 4 wire (I was told since it was separated outbuilding, to run the 3 wires) Not sure if I just leave the crossover and connect all the circuits to the equipment ground? and where to I connect my ground rods? to the shop frame, equipment bus bar, or just to the panel box? All metal building, set on concrete, so no ground through frame.