A collection for “Cities” where all the cities will be stored. Just a single text field is needed for this to work. Let’s call it “Name”.
Then another collection called restaurants which has whatever properties you need and also a relational property to Cities collection. (One city can have many restaurants but each restaurant belongs to one city).
Now you need to have the drop down menu on screen one with a button next to it or below it that links to screen 2.
In screen two you will make a list of restaurants.
You will then add a filter to this list. Like the image below but replace “event” with restaurant.
Just a side note but you can do this entirely on a single screen if you so wish and the restaurants in the list will update in real time with the selection of the city.