Create an Automation Command for each of your products.
Place the Automation Commands Buttons on a Custom Entity Screen.
Edit the Settings for the buttons to define Command Name and Command Value.
Create Rules for Automation Command Executed for the buttons with constraints that correlate to the settings on the Entity Screen.
Within those Rules, use Add Order Action to add a product to the Ticket.
The HTML Viewer Widget can be used to show online or offline webpages. You could size the viewer such that it does not take up the entire screen and place automation command buttons above, below, beside (near) each of you room pictures.
You will not be able to make the page interact with SambaPOS in most cases with v4. It may be possible in v5 via scripting and some Helper Objects.