Drawing tiles on the screen

Hi

I have been programing Symbian now for a while. However I have just started a game project, in which we use tiles and draw them onto the screen as the background. I have no experience of games or tiles. Does anyone know of a good doc I could read? I have dowloaded that 2D example off forum.nokia already. Trouble is, I don't understand how a one picture in mbm format is used to draw the entire background.

Thanks for any help.