Kohler K-6918 Installation And Care Manual page 9

Retainer
3/8" (10 mm)
Hex Shaft
6. Install the Wall Kit
Thread the notched pegs onto the threaded rods, leaving a 3/8"
(10 mm) gap on the rods.
Position the pegs with the notches facing down.
Insert the hex shaft into the receiver, then position the assembly
into the underside of the bowl and align with the holes in the
back of the bowl.
Install the retainer into the holes on the back of the toilet bowl,
and snap into the end of the receiver.
Kohler Co. 9 1287824-2-A