I use a side-firebox smoker that separates the fire from the cooking chamber.
If the flame were directly underneath, the meat would cook from direct flame and heat (grilling) too fast to be smoked. Tink of smoking as Slow Cooking.
Slow Cooking can break down tougher cuts of meat, the fibers and muscle to make it more tender.
example:
The box on the right side is the fire box, the larger chamber is the smoking/cooking chamber. This is a nice type of smoker for home use.
But we are not at home, we are in a SHTF/Canoe Overturned/Lost our gear/ Lost in the Wilderness survival situation. Sorry to burst your bubble of backyard grillin with a cold beer.
In the wilderness we would have to get pretty elaborate and/or expend a lot of energy to build a smoker that could contain deent sized pieces of meat. What we would need is an expediant way to smoke the meat, that doesn't take many hours to construct, because it can take hours to do the cooking anyway.
A Dokata Pit fire might give what you need for smoking, but I have no experience with them, except for what I have read and pictures I have seen.
Here is a very crude drawing of what I had in mind:
It is a standard 3-pole set-up over your fire, but you make a sort of teepee at the top, to help gather and route the smoke around the meat before it goes skyward. Easy to construct. The important part would be that the poles are high enough and/or the fire is burning low enough, that it doesn't cook the food too quickly.
At home you would use a meat thermometer, or by experience, to know when the meat is done. It should be warm in the middle. You will see a visible smoke ring extending form the outer portion of the meat inward. It is pinkish in color, which sometimes leads people to think the meat is still rare. the smoke ring should be at least 1/4" thick into the meat, but more is fine, isn't going to hurt it.
The smokey outer layer/crust is the first line of defense against bacteria.
For practice, You can use a standard grill, like a weber, to smoke meat. Just get a piece of sheet metal (not galvanized, yuck!) and build a small fire off to one side, and use the sheet metal to partition the flames away from the meat. Place the meat on the other side, and cook as slowly as you can.
Add woodchips as necessary to keep the warmth and smoke going. you can use a large coffee can to contain the fire, , but i would "burn it off" to get rid of any paint or writing printed on it before using it in the grill.
Chicken pieces are good to start with, as it doesn't take near as long as a big gnarly hunk of Pork. It usually takes me about 1.5 hours to smoke chicken breasts and thighs, maybe a little longer. Using the Weber method it'll be shorter since the fire is in the same box with the meat. Use an instant meat thermometer to check the chicken parts for done-ness.
Most thermometers will have an accompnaying chart showing beef, pork, chicken recommended temps.