If a B-body is like my A-body, it just attaches to one of the dash frame studs.(the upper studs that hold the column to the dash frame) The upper column bracket has white plastic bushings on it where the column mounts to the dash frame so it's insulated from a ground. My Challenger doesn't use any of those plastic bushings so no ground wire was used.

Yes The stud on the dash frame. Install the nut to hold the column in place, then another nut to hold the ground wire.(this is how it was on my 68 A-body)