Start by searching google about pulled pork. There's a ton of info out there. Someone mentioned cooking the butts to 205 then pulling, but that's not entirely true, you have to le it sit for About an hour or so foiled up before you start, that meat is really hot
How I do mine, smoke until internal gets to about 165 -170. Then I double wrap in foil with a bit of my mop and keep it going until it gets to 205. Take it out if the foil and cook it some more maybe an hour and then wrap again and let cool before I start shredding it up.
Sometimes I will cheat when I get to the wrapping part and put it in my oven at 250 for a few hours. It's not taking on any smoke flavor at this point since it's wrapped up and depending on the size the next 40 degrees can take a long time to climb.
As I said there are hundreds of different ways to cook shoulder so do some research and it'll work out right