Strip the servo wires and the ribbon cable. Solder them together with heat shrink.
Picture 1 and 2
Measure and cut a length of ribbon cable long enough to reach the front of the bike. Connect Molex pin terminals to the other end of the ribbon cable and insert them into the 3 pin Molex connector. Make sure the orientation is compatible with the the connector on your protoboard.
Route the ribbon cable to the front of the bike following the original cabling using hockey tape. Secure the original cable to the frame with tape if you don't want to completely remove it from your bike.
Picture 3 and 4
Place the buttons comfortably near the derailleur lever on the handle bar and velcro it in place
Attach the controller to your bike and connect the wires to the servo and button using the Universal Ram Mount
Picture 6 and 7