Assuming you have the 2.5 engine, the water pump is driven off the timing belt.
Yes, the internal parts of the pump can rust, and effect water circulation.
Coolant is sucked in from the lower radiator hose, pumped into both sides of the block, through the block, up into both heads, through the heads, out the front of both heads into the intake manifold, out through the thermostat housing, into the upper radiator hose and back into the radiator. All coolant connections on the exterior of the water pump are return/suction.
There are several manuals on the market that deal with such matters. They include diagrams and step by step instructions.
Such procedures are difficult to explain to someone with no mechanical knowledge.
If you need to ask such a question then it would be advisable to take the vehicle to a competent mechanic.
Some model of pumps labeled 'Menards' are made by Superior Pumps. I have never dealt with this brand and know nothing about them.