There has been tons of discussion on this subject.. I'd suggest you go to the top of the page.. click on "FIND" and put in "pulled pork". You'll find lots of great info.. The FIND may be the most under utilized feature of this forum (???). As an alternative.. go to the home page of Cookshack and click on "Cooking" and then on "Smokin Okies Guides".. he is the resident expert and has put in a ton of work providing these most excellent guides.
My process is simple.. I apply French's Yellow Mustard to the outside and then rub in my favorite rub (The mustard does not linger and cause the meat to taste like mustard later.. I don't know why, but it does a great job of holding the rub on the meat)
Prep the smoker by foiling and add 3-4 oz of your favorite wood.. I use apple and hickory or simply oak (MY favorite).. insert the probe of the digital thermometer, put on the middle shelf and set the smoker to 250º and let 'er rip. In my smoker, a small butt like this takes about 6-8 hours, depending on the amount of fat or whatever it is that causes time variations.
I happen to let it cook to 195º, pull it out and wrap in foil and put in a small picnic cooler with a bunch of old towels for about an hour or two.. depending on when dinner time is.. then pull it out and pull it, mixing on a tad more of CS's rib rub.
It's such a forgiving product.. you have a lot of leeway, one of the reasons it is so highly recommended as a first cook.
BTW, if you don't want to pull it.. you can cook to a lower temp (say, 180) and slice it.
BTW2.. if you have a bone-in piece.. keep the probe away from the bone.
BTW3.. WELCOME to the forum