Multiplayer usage on Unity Facebook SDK games

I found some tutorials based on how to set up network for multiplayer. On the other hand there are also many tutorials how to build simple Facebook SDK games. But unfortunately I didn't found any understandable information or tutorials how to set up very basic multiplayer game for Facebook SDK, which uses Unity Web Player?

The large amount of multiplayer games on Facebook show that this question should be well known, but I can't find any information how to do that properly. If you know some tutorials, guidelines or just simple steps, could you drop this info here?