Well i'm not a DBP coder myself but all programming languages use the same logic...
-------How to implement multiplayer features-------
You've said you have established a connection to both computers
Well done, the first parts done
A.) To make it more understandable i'd suggest creating a simple messanger program, all you have to do is send strings a.k.a. words to each other, read them in blah blah read them out
Simple diagram
Input (words) - Processing(To other computer) - Output(To screen)
-------next-------
Once you've done this you'll understand how to send data accross, you can change the data to be player positions, update those on the screen etc.. etc.. and there you go it's a start and i'm sure you'll get the hang of it if you keep trying.
Hope it helps, sorry about no code I only program in C++/VB/DBC/Java....