You will get some build up on the interior of your smoker, whether you close dampers/vents or not. Just don't over smoke and use the proper woods. Hardwoods do not create as much creosote as pines and softwoods.
you did state if you threw all the coals in there lite by the chimney smoker or did the minion method, which will hold the temps down. With no water pan, you might be able to add one to your grill area, but I am not real familiar with this smoker so may have to defer to others.
try again, but pyramid the coals, only a little lighter fluid in the dead center, enough to seep down abit, then light that and let the heat spread. Some will light just a half a dozen coals with the chimney, then add those coal and pryamid the unlit coals over them.