Well first off you need to oil your smoker. Go get some veggi oil. And coat the smoker. Then get as hot of a fire as you can going. (I'd put coals in the main barrel) Then let it burn itself out. It will help inhibit rust.
as for cooking It kinda depends on what you want to do.
Me, I typically don't do whole chickens, takes to long. So quarter it out. (unless you're going to stuff it like a turkey) Also, one chicken isn't enough food for the work and time that goes into it. Go get yourself one of those bags of chicken quarters. Typically what I'll do, with chicken, is get a 10 pound bag of quarters, and then a bag of breasts, (if I can find em). I like to mix up some BBQ sauce with brown sugar, and maybe some apple cider vinegar. And I"ll baste the chicken while it is smoking.
You can definately smoke your meat with just charcoal, espcially chicken. You can get a great smokey flavor. If I'm going to do beef, I'd get wood or a mix.
With Chicken, to me, I cook it warmer. Around 300-ish don't wanna go above 350. It takes less time, (usually I can do it in 3-4 hours) and on less charcoal. What I typically do is get a good fire going, with charcoal using one of
these, then Put it in the box. Then I'll pour an equal amount of charcoal on top. (that is usually enough for quarters. Then plop the chicken on. Don't wrap it in foil. The juices and stuff help cure the pit. I'll then periodically check it, baste the chicken. And make sure your grill isn't getting too hot. You just kind of have to play with the air flow, and see what happens. That is the tricky stuff. Usually, bc I cook chicken hotter, I have to rotate the pieces away from the fire box. And give it 4-6 inches of space.