The simplest, most basic movement out of the shoulder might mean simply putting a little pressure on the side of the shoulder and rewarding the horse for moving away from the pressure. The same may be done putting pressure on the front of the shoulder and rewarding a backward movement. These actions and responses do not, however, correlate to riding as much as some other exercises.
For example, if I want a horse to move its front end to the side, I use my leg approximately at the girth rather than drawing it forward to put pressure on the shoulder. Therefore, on the ground, I might apply pressure with my hand or the handle of a crop at this same spot and reward a positive response of moving away from pressure.