Hello Nag,
For question 1: When your bin is empty, system will trigger creation of a new production order. KANBAN managed materials have planning type ND (No Planning) as they are planned via KANBAN.
For question 2: The process is same, difference being GR will cause the KANBAN bin to be set to FULL
For question 3: Please go through below documents,
KANBAN Execution- Step by Step Approach
KANBAN Process for External Procurement
Also SAP help provides lot of information .
Hope this helps.
Best Regards,
Ameya B.