We at Celitech (www.celitech.com) have been working with hospitality partners to offer cellular data for travelers and have seen similar concepts but on long-term agreement basis, which might be restricting this market. The platform suggested here, offering short-term space rentals for product ads or demo's can create many new opportunities for a wider variety of businesses who'd find such concept more feasible. To validate this concept, you may want to build a minimum-viable-product which can be a basic website that you can test with targeted customers and space providers. Besides the website and its UX, you need to make sure that whatever ad/demo material your customer wants to show is totally compatible with the space where it'll be used. Once you have a couple "wins" you can expand, and while initially the service trial can be free, once you prove it is viable for both ends (the advertising customer & the space provider) then you may consider charging a commission on the space rental fees. Additional services you can offer later to your customers are ad/banner/demo designs & prints that would fit your listed spaces.

You may want to check what facebook did in this space and why it didn't work so far: https://www.nytimes.com/2018/06/27/technology/facebook-drone-internet.html

Clones don't look professional to your customers and may not allow you to try and test different features. If you're not a web developer, creating a website from scratch can be challenging but you can select a website builder online (for a minimal charge) to swiftly help you build your own website (with no coding).