NEED HELP - BASIC DESIGN TABLES

I have been searching around for some 'basic' info on design tables.  I have never made a design table but it shouldn't be that tricky?  I am trying to create a table and link it to a round disk, I want to be able to change the diameter and some hole locations using a design table.  I'm sure this issue has been discussed and I did find some samples but never found how the samples were created.  Can someone point me in the right direction.  Thanks, Chris

SolidworksConfigurations design Tables