Connected. And after ?

Hello.
I would like make a mmorpg. (it’s direct, i know)
I can connect to my server . And after ? How to make a player appear on the screen of all others?
And… How to send informations to a DB ?
Thank you all

this is a short answer
check this tutorial to start with

http://cgcookie.com/unity/2011/12/20/introduction-to-networking-in-unity/

and for a DB there are many different ways