Kohler K-3797 Installation And Care Manual page 40

Mark the Pipes - Bowl Side (cont.)
Apply silicone plumbers grease to the outside of the inlet pipe
gasket.
Firmly insert the gasket end of the inlet pipe into the water inlet,
pushing until it contacts the bowl.
Position a level or other straight edge device across the back of
the bowl.
Mark the inlet pipe at the back edge of the bowl using the level
as a guide.
1145594-2-C 4 Kohler Co.