the different glass dividers make sure there are no bubbles getting into your refugium and retun pump.
To make them you can get already cut sheets of glass or acrylic at your hardware store, or you can guy tank dividers.
If you tank isnt drilled for an overflow then you will need a HOB overflow box. Im going to make one soon, just working out the plans. But you might want to paint the back of your tank cause they are bulky, and will look realy big on a 10 gallon. Or you can get a HOB refugium. They have one made by Aqua C. A refuge is good for all tanks, so jsut because yours is small, doesnt mean it wouldnt do any good. It will acutaly do better because it will give you a lot more water volume as well as the standard benitifs.
The last space has a lower water level because of the pump or powerhead that is pumping water back into your tank.