Controls
Mouse or touch. Drag a sticker in the direction you want that layer to go. Middle layers turn too. Flick for a quick turn, drag further for a double.
Rotating the view. Drag near the cube to tumble it. Sweep around the outside of the cube to tilt it like a steering wheel, which is how you straighten a crooked face. On touch, twist with two fingers.
Keyboard. Moves are relative to how you are holding the cube. Cube rotations (x, y, z) never count as moves.