Responsibilities that the Connector developers have to implement:
If you want to start creating your connector right away go to Write your own Your Own Connector From from Scratch
Responsibilities of the Connector Framework (you don't have to worry about this):
The following diagram illustrates how the Connector Framework interacts with the connector implementation in order to run a crawl:
If you want to learn more about the Connector Framework check out NoSQL Connector Framework Overview.