H&S A10 F2000 Need Help

[Choate515]

I Ordered a H&S 90-F1000 but received a A10-2000, I cannot figure out how this one is suppose to work. I put it in my sump and hand filled it to the overflow but cannot see how it draws water into it. I did try adding a 9" piece of tubing to the top barb but again I don't see how that will draw water into the skimmer.