[modeller_usage] Reg modeller

I would like to understand the link below. I am not quite sure what each of those numbers mean, although the link does mention, can somebody clearly explain what those numbers are in restraints panel?

http://salilab.org/modeller/8v1/manual/node157.html#SECTION:atomid

Also, I would like to restrain N-N distance rather than C-alpha C-alpha. How do I make those changes?

Thanks a lot

Manju