I recommend Tag Editor since it’ll make your life a lot easier. You need to tag areas you want the NPCs to walk on as pathfindable. Weird name in retrospect I’ll most likely change it in an upcoming build. But for now, that’s what you need to tag your floors as.
For now, sitting and holding tools isn’t a thing that is supported. I tried to get sitting working earlier but due to the way Roblox does navmeshes it doesn’t work correctly. I’ll see if I can come up with a solution however. For the tools, not sure if that will ever be supported. That’s something you’d have to add yourself in an extension to the script.