Auto's are extremely difficult. In case of engine/motor failure the rotor system is powered by the upward flow of air through the rotor disc. The heli will not do it by itself. If the Tx is turned off it''ll drop like a stone.

For an auto you need some foward airspeed. This will keep the rotor spinning and maintain as much headspeed as possible. Rotor RPM's have to be maintained throughout descent. You'd probably have to use a fairly low collective setting to miantain headspeed. Then a few feet (not sure how much exactly) from the ground you'd flare the heli and pull in more collective. All that stored energy in the rotorhead now translates into lift and will alllow the heli a nice soft landing.