The way PBEM has worked for me this way using a pre-made scenario:
1. Player 1 picks particulars and password, sends to P2.
2. P2 assigns password, send back to P1.
3. P1 moves, send to p2.
4. P2 moves, calcs and send to p1.
5. P1 watches and sends to P2.
6. P2 watches, moves and the process starts all over again.
There is a bug, however, in the PBEM works. Infantry will not move out on foot the first turn.