This is from Alton’s series Good Eats in which he converts 2 clay pots into a backyard smoker. You can probably find a used hot plate at Goodwill or similar thirft stores. The clay pots should be new, otherwise you run the risk of adding ‘unpleasant’ flavors to your meat. Also note the size of his shoulder as compared to the size of the clay pots. Most shoulders (known and labeled as a picnic or Boston butt) come packaged whole and the hunk he is smoking is about half of that. He did trim some of the fat cap off as no smoke can penetrate the fat and flavor the meat inside. Only meat that is exposed to smoke will absorb the smoke flavor. The fat typically just runs down the side of the meat and into your smoker or drip pan. The more fat on the outside just results in more fat being rendered off and into your smoker. There are different theories as to fat cap up or down and if you have a drip pan I suggest fat cap up. Otherwise the fat should be placed between the meat and heat source. Some even start with the cap up and flip the meat halfway through. Pork shoulder is relatively bullet-proof and you can over cook it without doing a lot of damage. Most meat you cook for a long time via the slow and low can handle over cooking. The meat itself contains plenty of fat and connective tissue and only extended cooking at low temperatures can break them down.