transferring data from an esp32 to the app

hello, I need help with my app, I have a system of ultrasonic sensors that detects whether the space in a parking lot is occupied or unoccupied, the thing is that I want the app to show the places that are being occupied by placing an image of a vehicle, as would be the programming of blocks?

note: to communicate the app with the microphone I am using bluetooth.

thank you