Tapping the hammer icon will display the build screen. Tabs are separated by their functionality, and tapping Details will show its effects. Some buildings will have limitations on how many that can be built. Expanding your city into key areas will increase this limitation up to a point.
Tapping the red arrow key will switch the game into relocation mode. Tap the building to lift it up and tap it on a different location to move it. Some buildings will show a yellow aura, and building on it will give the moving facility an extra boost.
Increasing a structure's level will improve its efficiency. Tap any building to show its resource and time requirements to increase a level. Multiple buildings can be queued, but limitations will change based on the game's progression.
Some facilities will have a level cap. Players are given the option to Rebuild the building once the requirements for it are met. Some buildings that are rebuilt take additional space than its original size, so moving the building first to an open space may be required.
Structures can be demolished if you are in need of open space. Demolishing a building will also take time, and players will not be able to recoup the resources that was put in to build it. You can also cancel the destruction process by going to the structure's Details screen and tapping the Cancel button.