As someone already said, fat side up. And I don't trim the fat all before I start smoking it. I usually trim some after, but you want the fat on there and rendering down into the meat while it's cooking. Also like others have said, I found a nice Bluetooth thermometer that gives you the internal temp of the meat and the ambient temp inside your smoker and it works great, it's called a Meater.

Anyway happy smoking and practice makes perfect 🤘🏼🍖🍗