Skint
Most civilians who get into loadmastering start on the ground with the likes of TNT/DHL etc and then with experience get the odd flight and progress.
Shuperstar
If you are a civvie Loadie you will know that most of the Brit one's are ex-RAF Movers and rarely an ex-RAF Loadmaster. Why? Because the Movers know payload is profit and it's them who PLAN the load and put it on and off. Planning sometimes takes 2-3 mins on a 90 min turnround. The RAF Loadie will have left the aircraft with the sharp end people to re-order his cheesecakes for the next segment.