OK, I know this one, it's sooo easy! We do this all the time w/ beef, chicken, pork.
All you do is put the beef in the crockpot, pour the BBQ sauce over it, & turn it to high. After an hour or so all the juices are coming out & it's looking a bit like BBQ stew. Stir it up & see if the meat is falling apart yet. Usually happens after 2 hours for me. Once it's falling apart when you poke at it
I use 2 forks. I do a stab-and-shred type thing using the 2 forks. Stab a chunk of meat w/ one fork to hold it down & use the other fork to shred. Repeat until meat is shredded to your taste. Then I usually put a bit more BBQ sauce in there & stir it up. I leave it on high until the juices & sauce are cooked down to my liking. DH likes it just a tiny bit soupy. If there's a lot of juice & I want to hurry the cooking down process, I'll leave the lid off for awhile. Once it's where you want it, you can keep the lid on w/ it on low until everyone's ready to eat. If you happen to let it cook down until it's too dry, simply add some more BBQ sauce & maybe 1/4 cup water & you're good to go.
Hope that helps some!