540 Gen VI Coolant Flow Questions

I am putting a new Edelbrock 8851 high volume water pump on a Gen VI 540 cubic inch large block. I have a 1970 chevelle and I will be using the heater with a new core. It has been ages since I took off the hoses and I was hoping for some help to confirm which hose goes where. The hoses are two sizes best I remember.

I recollect that the smaller hose attaches to the water pump and to the smaller fitting on the heater core. Similar, the larger hose from the larger fitting of the heater core and then runs to a connection on the intake manifold to the space under the thermostat.

I remember seeing somewhere that there was a short hose that went from the intake also from a connection under the thermostat to the water pump connection near the one for the heater. I wonder if I need to hook that up. I just read that a person might only want to hook up this short hose if your not using the heater.

I was wondering if anyone knew the purpose of needing to bypass the engine with any coolant flow thru either the heater or this short hose. I can only guess that a person wants to mix the radiator coolant and engine coolant so that when the thermostat opens there isn't a huge difference in temp between the two??????