There are two styles of keyboard moves: XYZ moves, described here, and Singmaster moves, which are described in the section Singmaster Moves.
To move the cube with XYZ, first use key X, Y or Z to select an axis. On the screen, the X axis runs from left to right, the Y axis from bottom to top and the Z axis towards you from behind the screen. Now, to move the whole cube use key C or to move a slice use keys 1 to 6 (to select a slice number).
Finally use the left-arrow key for anti-clockwise rotation and right-arrow for clockwise. The slice that is going to move (numbered 1 to 6) will blink, until you hit an arrow key.
You can make further moves by using one, two or three of the above keys. For example, to move the same slice again, just hit an arrow key.
If you have used the right mouse button to rotate the cube, the meanings of X, Y and Z may have changed, so the cube is automatically realigned, using the → action, before the keyboard move you have requested can be executed.