Jeni, the smaller bowl of the 2 is a water pan, the larger being the charcoal pan. This has many similarities to Brinkmann Gourmet, which is one of several smokers I own. The main differences separating the two being the combustion air intake holes on the base, and the single hole in the center of the charcoal pan with your Coleman, while the Gourmet has a single intake on the base and multiple slotted holes towards the outside along with smaller holes on the sides of the charcoal pan. The Gourmet is basically an improved version of what you have, and I have done several mods to help it perform even better.
The water pan should fit onto 3 stepped tabs which will be located approximately half-way up the side access door opening. You install the water pan centered in the barrel, then a cooking grate should fit directly over the water pan on the same support tabs. The lower grate will get more steam from the water pan than smoke, while the upper grate should get a better balance of smoke and humidity. The water pan also acts as a heat baffle to allow for indirect cooking, and should always be used with vertical smokers to prevent meat drippings from disturbing the charcoal fire causing air-borne ashes to be carried onto your food. You get this with charcoal grills, however it is much shorter duration when grilling. While smoking, cooking takes longer, and the ash build-up on your food would (can) be quite unpleasant without the water pan installed.
With this smoker, you have no fire control (intake air draft control), meaning, chamber temps will swing wildly when you add hot coals or when the fire is burning down. So, your main method to control heat is to control the amount of fuel you add to the fire. Regular fire tending is required to keep temps in check. A small hot fire seems to work best, and you make the fire a bit larger when you need more heat. Start small and build it up as needed. It takes a bit of practice to learn where the base-line is for a particular smoker, but it's not that difficult. I have tried the Minion Method for fire control with my Gourmet after making intake draft control mods as well as many others, and temps got out of control rather quickly, so keeping the fuel amount and fire smaller will likely give the best results.
A few basics on smoke chamber humidity and how your meats cook with smoke:
Water is used to control high-temp spikes (evaporating water cools the smoke chamber). You can also use washed play sand or pea gravel as a thermal sink (dry smoke chamber), which will help keep temps more stable, but will not control high-temp spikes. Using water (wet smoke chamber) requires more fuel to get temps high enough (more water used = more fuel needed).
Wet smoking allows more smoke flavoring by keeping the meat surface moist and the fibers loose. High finished temps (internal temp of meat) while wet smoking can cause a bit drier interior by keeping the surface meat fibers loose and porous which allows interior moisture to evaporate.
Dry smoking allows less time for smoke reaction with the meat as the fibers will tighten up and seal more quickly. This also allows for a moister finished product when taken to higher finished temps, such as with brisket or pork shoulder cuts.
You can start a smoke on larger cuts of meat with a wet smoke chamber (water in a foil drip-catch on top of the pan), (drip-catch to keep your thermal mass from getting nasty with drippings) while having washed pea gravel or sand in the pan itself. Allow the water to evaporate after several hours (stop refilling) and as the smoke chamber humidity drops, the meat's surface will become less porous and reduce interior moisture evaporation. This gives a decent amount of smoke reaction and holds onto more natural moisture in the meat.
I have experimented with the above method recently and find that it works very well for a balance of smoke and moisture retention.
If you need help learning what makes this smoker happy after you prep and season it up, I can give you more tips. Oh, and by the looks of the charcoal pan, I would not plan any long smokes in it until you do mods for ash fall-out from the coal-bed. Ash build-up will kill the fire, and you can keep adding hot coals to bring temps up, but it won't last. Eventually, you end up with a charcoal pan full of dead briquettes and the meat going into the oven to finish cooking it.
The barrel and base of the smoker should fit reasonably close together when assembled. If they do not, it will allow excess air into the smoke chamber and cause additional temp control issues. Sometimes, just a slight bend in the barrel or base can create a better fit. When assembled, you can check the fit in low light with a flashlight shining inside, while you look for light on the outside at the joint of the base/barrel. This will tell you right away if they fit very well or not, and help identify where the fit can be improved.
Let us know if you need any help or ideas how to get started with the little beast. You can cold smoke bacon and cheese in just about anything (within reason), and with a cold smoke generator of some sort. The
AMNPS (from
A-Maze-N-Products) is a dandy tool for cold smoking, and with the proper methods depending on the smoker heat source, can be used in hot smoking applications as well.
I hope I gave you enough info to help you have a better idea what to expect as you start preparing for your new hobby (uh, soon to be addiction) of smoking meats.
Eric