What to do with my ten gallon.

The overflow box takes the water out of the main tank and drains it to the sump via siphon.
Reef Aquarium Filtration: Eshopps Overflow Boxes

Then on the other end of the sump you have a return pump that pumps water back into the main tank. I like the mag drive pumps I have one works great.

Danner Model Supreme Pumps w/ Fractionating Impeller

Here is a basic diagram:
Aquarium Supplies | Filtration Diagram | Vivid Aquariums