It seems that you are on a mobile device. You need a keyboard to control the cube.
The key i opens/closes this menu.
The Arrow keys rotate the cube.
Alternatively, you can drag with your mouse.
The keys +/- zoom the cube in/out.
The key t (resp. T) rotates the top layer.
The key d (resp. D) rotates the down layer.
The key l (resp. L) rotates the left layer.
The key r (resp. R) rotates the right layer.
The key f (resp. F) rotates the front layer.
The key b (resp. B) rotates the back layer.
The key e (resp. E) rotates the equator layer.
The key m (resp. M) rotates the middle layer.
The key s (resp. S) rotates the standing layer.
The key u undoes the last layer rotation.
The key U resets the whole cube.
The key X scrambles the cube.
The key c toggles transparent mode.