How do I get internet multiplayer to my game? Rooms/ world type, almost like A MMO RPG?
Start by reading the manual on networked multiplayer.
Realtime networking is a complex field, but with Unity we have made it extremely simple to achieve. However, it is still best to understand the breadth and depth involved with creating any kind of network game. This section will explain the fundamentals of networking concepts, and the Unity-specific executions of these concepts for you to use.
If you have never created a network game before it is highly recommended that you read this guide in detail before attempting to create one.