To be technically correct if the outlet has a brass screw and a silver screw the black wire should be to the brass and the white wire to the silver. But for 220V applications that doesn't really matter because both the white and black are "hot".

The neutral wires and ground wires are bonded together in the breaker box. This is the ONLY location where they are allowed to bond together. Once you open the breaker panel it will be fairly obvious where to install the green wire. But even if you bond it to the neutral bus within the breaker panel it will still be grounded and safe.

Make sure you use a "double-ganged" breaker. It's 2 single breakers joined together with a tab. And make sure you install it such that one breaker contacts phase 1 of the main and the other breaker contacts phase 2 of the main. If you don't you'll wind up with only 120V at the outlet.