If you are rights side up foward than the stick movements are

left rudder, collective like a real loop, and starting from down cyclic you rotate it clockwise. It is CCW if it is right rudder.

When you reach bottom cyclic again you should be finished with the loop.

There are four points that are key to getting it right. 25%,50%, 75% and 100% into the loop.

25%, the heli should be knife edge and the boom should be parallell to the ground. The cyclic should be left.

50%, the heli should be at the peak flying backwards inverted and you whould be adding up stick on the cyclic.

75%, knifeedge, you should be adding right cyclic about now.

100% it should be the same place where you started going foward. You should have just let go of the bottom cyclic and you should start going foward again.

Keep in mind the cyclic stick should be rotating at the same rate as the rudder. It is one piroette stretched in a loop.

I have only done these in the simulator because this is a hard manuever to do. I can do it in the sim without too much problem.
This manuever is too hard to have full control over the heli at every single second. What I want to tell you is that anyone can do this manuever, but it takes great skill to do it right and have full control.