Problem With Render Passes

[mindsample]

Hello EyeryOne
I am Smita From India.
I am new for Combustion and also for Animation Field, So pls. help me for Following quastions :

1. What is Render Passes ?
2. How To use Render Passes in Combustion ?

So please me.

or also tell me if any tutorials are aviable on this topics.

My Mail Id : smita84_patel@yahoo.com

Thanks