if all that you require is a 2 player game;
step 1 - make the game playable offline
one player vs the computer.
step 2 - Enable multiplayer by replacing the AI with
the other players movements.
Sounds simple, but step 1 is the hardest part.
For step 2, I would place all player data into a memblock
(or, if using DBC not enhanced, into a string var) and send
that data about every 0.1 seconds and on the receive side,
simply read this data back out and place it where the AI used to be.
So, the challange on step 2 is
A - creating the connection between players
B - Combining data into a memblock or string
C - Reading the memblock or string into the AI vars
The problem is not too tough if you tackle each part by itself.