I suggest you follow the instructions that come with the toilet. Those instructions vary slightly with the make/model.
However, it should help you to know that toilets designed to use fresh water do not have an intake pump...they use pressurized fresh water controlled by a solenoid valve that can either be inside the toilet or in the intake line--which is teed into cold water line-usually the line that feeds the head sink. That solenoid valve works kinda like a faucet on a sink...pushing the flush button opens it to allow water to come into the toilet, closes to shut off the flow of flush water. It's necessary for the boat's main water pump to be on to provide the water pressure. The head intake thru-hull can be re-purposed to supply water to a sea water wash down pump or hvac water pump or just kept closed.
--Peggie