Just to clarify, you're looking for advice on plumbing your existing sump to your tank, right? You plan to use a siphon overflow that hangs on the back of your display right?
The basic setup is that water is pumped from the return pump section of your sump (center section in your case), through hose or pipe to a nozzle that's located just under the surface of the water in the display tank. As water is pumped into the display tank, the water level starts to go up, and as it does it overflows into a compartment of the HOB (hang on back) siphon overflow that's inside the tank. The water then gets sucked over the edge of the tank into another compartment of the HOB overflow that's on the outside of the tank. From there it drains through a hose or pipe into the drain section of your sump (the one with 3 glass baffles dividing it from the return pump section).
That's the basic flow. Tell us what part you want more details about.
Nate