| Before we go on, this is to oppose direct heat, which is pretty much how most of your meats are cooked on a barbecue. You know, hamburgers, hot dogs, sausages, shrimp, steaks, etc.
Indirect heat is a method of barbecuing that offsets the heat source from the food. Whereas direct heat is great for a steak, it doesn't do so well if you want to cook a large chunk of meat such as a roast on your barbecue and don't have a rotisserie handy. It's also a requisite technique for cooking beer can chicken, because you just can't do that on a rotisserie. The side effect is that your roast (or chicken, or whatever) comes out incredibly juicy and can now actually be smoked. In short, you're basically turning your barbecue into an oven.
Because there are several grill configurations (there are still more ways to leave your lover than grill configurations), there are naturally several ways to do this that revolve around one simple principle - don't put the meat directly over the flame. Charcoal grills (or just coal grills) run the gamut from the small generic sheet metal pan on legs suitable for burgers and steaks to full blown cooking centers resembling upended oil barrels with hotboxes; some will resemble the filter tank on your swimming pool. I'll try to give tips here for everything.
Also, I make one assumption - that you are using charcoal and lighter fluid, as opposed to charcoal with starter units (where you put a lit newspaper underneath the coals in a contraption that resembles a coffee tin with a handle). That sometimes works better - your call. In any case, this node isn't for instructions on how to light a barbecue.
* Gas grills are a bit different than a coal grill - you simply start all but one or two burner(s), and the unignited portion is where you place your meat. Make sure you use a low setting, and when you add your smoke chips, follow your manufacturer's directions.
For coal grills, follow one of these, and note that you add your smoke chips to the coals directly:
* For a small hibachi style barbecue, forget it. Go get yourself a larger grill or just stick to burgers and dogs.
* Smaller barbecues can simply use the foil baking pan as a centerpoint to the grill, and place your coals around that. This technique is described on the back of about any bag of Kingsford brand charcoal and can also be used in those chamber style grills that look like large black propane tanks with a front door.
* A particular model of New Braunsfels brand coal grill comes with a "coal box" on the left side, and a smokestack on the right. If your barbecue is one such model, you're all set as we speak, just load your coals into that box and light up - but make sure that you keep a close eye on your meat, as the meat closer to the hotbox will cook faster than the back end. Also, if you're not careful, half your meat might come out only partly cooked - on chicken, this can be disastrous.
* Finally, there's those oil-drum convert units you see sometimes. On those, the trick is to place the coals on either side of the chamber and light up - your meat will just go right in the middle.
What it boils down to is that whatever works is what you do. Get creative, that sort of thing. And happy barbecuing. | 
