You are not dense Brother. If you are trying to learn and have never really had the opportunity to do a thing, then learning and asking questions is the antithesis of being dense.
I mean, usually you find a water pan up high and a drip pan lower and you actually want the water to defuse during the smoking process, which is why it's located higher. You don't want it filled with grease and no water. The grease pan is lower because you don't want any grease fire starting so the pan obviously collects it to prevent this. However, a lot of people do use those drippings for everything from adding moisture back into the meet to adding to other things like beans or what have you to gravy etc. Those smokers out there are pretty industrious!