Everything you ever wanted to know about cooling systems.
I am pretty sure you want the hose that comes from the cooling system to the inlet of the expansion tank to be attached to the lowest PRESSURE point in the system. This will also be the coolest temp coolant and will be the returned coolant from the radiator. On your chart that would be the hose coming from #9 to the pump inlet. Put the fitting on the hose (pipe) BEFORE the inlet to the pump. This is the lowest pressure point in the entire system just ahead of the pump impeller.
None of the ports on this log-type manifold can be used for this because the pump itself is external to the system and therefore its low-pressure inlet is remotely located. As you can see in the above picture of the LS pump you will not be blocking any of the ports on your manifold. All are used to accommodate your pump output to the motor and engine hot coolant return to the radiator.
So, let's start at the radiator cool water outlet: This hose is attached to the pump inlet after traveling down the side pod, and here is where you want to attach your expansion tank main feed. Then the main coolant flow is pumped from the pump outlet to the bottom AN port and bottom half of your manifold in your picture (the one attached to the square ports). The water then flows into the block and back out of the heads (round holes) and back into the top half of your manifold to the top AN port of your manifold. You will then attach this point to the hot side of the radiator after traveling down the other side of the car in the other side pod.
Air bleeds: the idea is to allow all the air in the system to return to the expansion tank. So one must come from the top of the radiator and the other from the top of the engine (heads and best at rear of them). If you install a heater. Then you will need to determine if air is getting trapped in it and if so add a third air bleed line from the top of the heater system to the expansion tank.
Main feed from coolant system to expansion tank: As above it must come from the lowest pressure point in the entire system and this is directly at the inlet face of the pump impeller. Place the main feed in the expansion tank on the bottom so that it is covered with coolant and the small bleed line at the top so that they return into the air at the top of the tank under the radiator cap.
The line to overflow tank: Run a line from the radiator cap blowoff port on the side of the fill neck to the bottom of the overflow tank. The overflow tank must not be pressurized. So a vent needs to be installed at the top of it. I like to do this with a hose that ends at the back of the car BEHIND the tires so that if the coolant comes out of the car it does not end up on the rear tires.
That is the entire coolant system routing.
My picture shows you (barely) my main expansion line feed. It's the AN fitting welded onto the tubing that is directly attached to the pump inlet. The other end is the silver steel braided line that goes to the bottom of the expansion tank (square aluminum tank). The pictures of the tank itself show the two bleed line inlets at the top and the bigger bung for the main feed at the bottom.