Which Hose for Install of Engine Coolant Heater on a V6 Camry LE

I purchased a Kat's engine coolant heater (600W) that is to be installed within one of the radiator hoses of my '96 Camry LE V6.

My question, dumb as it may sound, is which coolant hose do I place it on?

The instructions contradict themselves by saying place it close to the water pump on the lower radiator hose. Upper hose goes to the water pump.

I appreciate any help/insight. Thanks.