Well i have the 125g version but is pretty close in design. Pic is the one 150g swf sells. Just put the eggcrate on the bottom lips. then bioballs,then filter tray,then filter pad, then cover and tighten the screw that locks it in place as pictured.
Overflow box is pretty simple. Just screw the pvc together thru the hole gasket on the inside and the pvc with the hex design on the outside and tighten. Then add the flexible hose to the bottom then to the filter. It will be a little hard to get on i used hot water to soften it . Put the overflow on the back of the tank , adjust the plastic screw to have it straight, add the skimmer box?(box with cuts on top) tighten the screw that holds it a little. You will probably move it later to get your water line where you want it. Then add the u tube. Long side should go on the back side. You can put the air hose in there for now in the middle of the u tube. Then add prefilter sponge.
Then you have to take care of the return. Place pump where you want it add ball valve if it is stronger gph than it can handle. Attach hose to spout of pump with plastic clamp or stainless steel but it will rust then run the hose to the top. Put u or j tube return where you want it, bring the hose up to the j return and cut to size. I give it a little extra otherwise it might sit crooked.
Then add water to the top of the tank and add water to the wetdry. Having some extra water is a good idea. Then siphon with the air hose till you see a small amount of bubbles then pull the air hose out. You can move the air hose around while your sucking. Then start the pump. Your water level should be stable in the tank and wetdry if it is running corectly. And move the skimmer box up or down to set your waterline then tighten.
