I see your a little confused on how to set this canister up correctly. I would reccomend you do the following.
First rinse the media in the canister and seal the motor head to the canister body to make it ready for operation.
Next place the canister in the desired location in your stand. Make sure the cord reaches an outlet and you have easy acess to removing the canister.
Cut two small pieces of the hose to fit between the canister and the valves. A small piece of roughly 2" works well. Attach these to the canister, then insert the valves. Make sure to properly tighten the nuts to lock the hose in.
Next position your spray bar and intake tube in the tank. Make sure they look nice from the front of the tank, so you don't have to move them later.
Lastly join a piece of the tubing from the input tube to the canister. Water comming in from the tank to the bottom of the canister. Don't forget to tighten down the nut. Lastly...
The water returning to the tank goes out through the top of the canister. Connect a piece of tubing to the top of the canister and measure it up to the spraybar. Don't connect it yet. Make a short hose connection between the spray bar and the elbow that goes over the side of the tank. Connect that. At this point all you should have to do to finish the connections is to connect the piece of hose from the canister to the elbow that goes over the side of the tank.
Give the hose from the top of the canister a quick suck, to start a siphon. The water should be comming up the intake tube and filling the canister. You have a few seconds to connect the last piece of tube before the canister fills, so go ahead and do that. Quick before the water starts comming out the tube
Once the air is out of the canister, go ahead and plug it in. Should work!
Hope this helps!