Way to go the music selection!

We use drywall returns instead of door casing, just like this door. But the jamb in the EKC3684 kit doesnt seem set up for that. After you installed the pocket door frame, what did you do to let you install drywall as a finished product without casing? In other words, what are the skinny lengths of drywall nailed to?

Won't the door just slide open even after being locked with that lock..?

Without question the most confusing installation video I've ever seen ....