[PyMOL] RMSD

Dear All,
I am relative new with PyMol and I am having trouble finding my way around. I wish to perform a rmsd for each atom  from 

1) a boundle of 20 conformers 
2) two different align structures, in PyMol such that the results of each atom pair can be displayed or plotted as a function of the amino acid sequence  in a pairwise manner. 

Can someone give me some tips on this?

Thanks as lot 
Celestine