I'm trying to get my npc merchant to own a shack I built for him the same as the crabbers shack in the game but I've had no luck , I've looked at Danatoth video tutorial but that seems to only apply to a house not shack and At the moment he just stands there day and night and the AI package tutorial on the skyrim wiki wont work because I think he needs to own the shack before they will work hope someone can help.

You can do this by Righting Clicking your cell in the Cell View, and click edit. Click the Interior Data tab, and select the owner NPC from the drop-down list.