Unfortunately, I don't really understand what you want to display.
If the number (address) of the building, then in most cases buildings do not contain such information.
If you want to display some of your own information, see UI Bubble Popup example scene.

I'm new to this asset for unity.
For my project, I want to create objects (just simple planes) on top of all blocks of buidlings with each an unique number that are connected to the map but that I can change the color and other variables of.
Depending on where you are on the map it should load these objects that are in the vicinity
Any idea's how I can do that?