Every button
There's no pointer to steer about. A coral ring sits in the middle of the screen and you move the city under it, the way a lot of console builders do it. The tile you're about to build on gets a coral outline.
The ring and the outline only show when the pad was the last thing you touched. Move the mouse and the pointer's back.
The pad buttons are fixed in this first version. The keyboard can be rebound to anything you like in Settings.