So I'm not sure how i would go about this so i came here to get some advice for you guy's

Here's an example i buy a shop/house and it comes with standard icon's like carpet but i want to change them by either replacing them or add a something over the top of it like an overlay. But i want to make it so only i can change the turf's in that place and no one else can.

I'm not sure how i would check what the player has in hand and how i would be able to change the ownership of each turf, unless I add area's for each turf.

If this explanation is terrible and I try to word it better just let me know.

I know how to check if they own that tile but i'm not sure how i would assign ownership to those tiles.
Any advice and/or help?