[MWilliams]

Hi! I am a new user of Openfoam. Thanks to the mostly self-explaining tutorials the beginning was not too difficult.

I am now trying to better understand the solver chtMultiRegionFoam in Openfoam 1.6. I would need some introduction to regions, zones and cell sets. Are these just lists of cells? Then, what is the conceptual difference between the three?
Which directory structure is required to read regions etc. from disc? In the multiRegionHeater tutorial I find something at constant/polyMesh/sets/<regionnames>, but also at constant/<regionnames>.

Does any kind of document exist that explains the usage of sets, zones and regions?

Regards,
Mike