You have a pretty wide choice of containers to place the smoker in. I have had success with a couple of different small, lidded barbecues, but the plain old cardboard box I used the other day also worked fantastically.
For the barbecue method, you simply place the smoker where you would put the coals and put the food on the grill - a lid for the barbecue, whether it comes with one or you fashion it yourself, is essential.
For the box method, I put the smoker on a metal baking tray to avoid any potential risk of fire, then balanced an oven shelf with the food to be smoked on two glass jars. After closing the box, I covered it with a large towel to make sure that no smoke escaped.
Your box/barbecue needs some venting - just a small hole or gap that a little oxygen can enter from. I felt that, to keep the smoke burning for all those hours, it needed some flow to achieve this.