Welcome to SMF! I use an MES so I'll tell you how I do things.
Before you put any meat in your smoker you're going to want to season your smoker. That's to burn off anything that might be left on the surfaces from the manufacturing process.
Spray the insides with cooking oil and then heat up your smoker. After an hour or so, add some wood chips and let it go an hour or two longer.
To smoke those butts, use a temperature of 225Â° or 250Â°. As far as how long, cook by the temperature of the meat, not by time. A VERY rough guide is an hour and a half per pound but I wouldn't trust that if you are trying to time a meal.
Often butts will plateau where the temp just stops moving. This is a good thing because all the connective tissues are breaking down, making the meat tender. The plateau can be anywhere from an hour to several hours.
I wrap them in foil at about 165Â°. For pulled pork I shoot for 205Â° for the final temperature. Then let them rest for an hour or so before pulling the meat. They should be so done that the bone pulls right out.
While they are smoking I either put them in aluminum pans or put pans under them to catch the juice that's dripping off of them. If I have them in a pan I draw the juices off every couple of hours. Let the juices cool so the fat sets up on top and then take it off. Put the rest back in with the meat.
Hope this helps.
Btw, I sometimes have trouble keeping the temps up on MES when it's cold or windy outside so you might want to consider some sort of windbreak... especially with the snow and ice Lincoln has had.
Good luck with the butts.