First of all before you can do this you must be able to do a 1990. You have to know which hand you wanna spin on usually the stronger one. Ok now before actually trying this move first practice by doing a regular handstand and lift up the hand that you don't spin on and place it over your spinning hand palm over palm, and try to balance like that for a few seconds, the longer you can stay up the better and practice a lot. Now u are ready to begin first start out by going into your 90 and once you are in the air you lift up your nonspinning hand and u start to spin place your free palm on top of your spinning hand and try to pull of some spins. This move is much easier than a 1990 but takes a week or two to get one solid rotation down so it shouldn't be too much. Just keep trying

-You don't spin on your fingers you spin on the bottom of your palm.
-You might wanna use a bandana or something under your hand when trying this for the first time when you start to get better take it off.