If you need help with the initial setup like connecting, entering a room and instantiating objects over the network, I would highly recommend easy PUN from the asset store. Use this in tandem with the PM PUN demos. It will save you so much trouble. Then you are mostly left with the other difficulties of setting up your actual sync logic which is no easy feat, depending on your game. You just have to study the crap out of everything, I don't think even a video can make it easier.
Another tip that I wish I knew earlier.. you can actually run 2 instances of the same Unity project so that you can test your game without needing to make a standalone build. This has a lot of benefits - much faster to iterate, and ability to better debug both player scenes. If you or anyone wants directions how to do this I can further explain.