Hi BigMike,
the last difference training was quite a while ago, so no papers just at hand.
From memory,
You need some theoretical part, covering the engines, especially the overspeed protection, possible different copckpit layout (Fuel-shut-off-lever-assembly, different switch- and fuse panels), VARTOMS (variable Rotorspeed and TQ Matching system)
as well as an smal amount of flying.
Greetings Flying Bull