2 quick easy questions

[khaosinc]

ahh the joys of being a newbie again... since I've never actually looked at a skimmer hooked up before.... how exactly does one hook one up. I have a box of pumps and such, so I assume one is for this one.
Does it pump in from the bottom, the little hole in that line is for the airline, and then returns through the white line?

 

[khaosinc]

and second, it seems obvious, but with the drilled holes in the tank, for the sump (theres 2 sets on the 210 gallon tank I got) I assume for each one, one is outlet, and the other is for a line to return the water to the tank after the pump?