I had the same thing, I guess. You can practise it with Under Pressure. You can look it up.
When I do it - and I am just learning this one, too - I start with the deck in my left hand, thumb and fingers along the bottom as for any fan. My right thumb is on the bottom of the deck, closer to my body than my left thumb, on the right corner. Fingers 1 and 2 are at the outer right corner. Then I basically rotate the deck around my right thumb, and my left thumb moves slightly out and away from me.
Also, I found that going slower helped a lot.