trying to figure out how to put this together

Hello, I've got a 20 gal high with a 10 gallon below, a 150 seaclone skimmer and 3 powerheads. I don't have a drilled tank so need to figure out an overflow (which I'm totally new to) and how to put this all together effectively. Right now I'm planning on using my ugf just to put the 2 powerheads on and to distribute some of the rock's weight but no gravel or sand; and then somehow use the other powerhead; and maybe incorporate the skimmer in this; to make the overflow. Any ideas on this?

 

for an overflow box you are going to need something like this.
Aquarium Overflow Boxes | Marine Depot

as far as making your own you can check here, I made one of these and used it for 6 months before buying a good one.they work pretty good.
http://www.3reef.com/forums/i-made/nice-cheap-diy-overflow-29396.html

or if you are handy with acrylic:
http://www.3reef.com/forums/i-made/building-weir-style-overflow-29456.html

also you dont use pumps on the overflow they are suction feed by gravity, the only pump you need will be in the sump to return the water to the tank.
hope this helps.

 

I have never had a tank that wasnt predrilled, but this is what you need (Or something like it)

Aquarium Filters: Continuous Siphon Overflow

 

Nice Cheap DIY Overflow thread was very informative. Thanks. Was there some reason you upgraded to a store bought? Ok, I'll have the overflow done any day now but for the return can I get a maxi jet mod and use it to pump the water back up? I may actually have my tank up and running, yea!