Units that consist of a single model, such as monsters, chariots, lone characters or sole survivors of annihilated units, are mostly moved the same as other units.
They move, wheel and march just like a larger unit. The one exception is that a single model can pivot on the spot as many times as it wishes over the course of its move. It can do so without penalty and so pivoting does not prevent models from marching, or even from shooting later in the turn. This represents the greater freedom of movement that an individual creature enjoys over its fellows in a ranked-up and disciplined unit; although a lone model that pivots on the spot does count as moving for the purposes of shooting and so on.
On some occasions, notably when charging, a lone model has to perform a wheel (when charging, a lone model must follow the normal charge rules, which do not allow pivots, only one wheel whilst moving, and another to 'close the door'). In this case, wheel from one of the front corners as you would for other units.