"floor plan" location

I’m making a desk booking app based on appsheet example app

It’s supposed to have 3 building and each of them should have 1 or more floor plans.
App arrives with 1 example floor plan that I’m unable to change.
I checked other threads where people provide links to their apps but I’m unable to find reference pointing at the plan.

I understand that it’s normally a URL pointing to public resource and should be listed in one of the tables in data. I’m assuming I’m missing something obvious but I think I went over everything multiple times. Even UX view that contains map just
Any tips on how I can locate it?

" To enable an XY image map, change the column definition of your location data to XY and add a link to your hosted image (as quoted text or an expression) in the Background image for the XY coordinates setting:"
From Working with Maps | AppSheet Help Center