You need to get it in a flat spin where the force of the spin keeps the sticks pointing away from each other. It will roll around your hand like a stick, but if the chain is too long, it will end up in the wrong place. You need the chain to be set to your hand.
To learn the hand-spin, the easiest method is to start with the ice-pick grip (chain hanging from the other end of the hand to the thumb) and start some nice reverse-grip figure eights. Nice and smooth. Then just release the stick, slow your hand and watch the loose stick come round. Grab it between the meat of your thumb and palm and keep it flowing.
Once you've got that, you'll have a feeling for how to flat-spin the sticks in the ice-pick grip. Then, you can move to the much harder foil-grip (standard position).
Good luck and practice with plastic if possible as this can go horribly wrong.