Hey Benjamin,

I know a little bit about the technique but not much - I never tried it. I think it might mean that you simply have to visualize your fingers moving as you are moving them. The movements have to be very subtle, of course.

The official tutorial for this is here. I would try typing in "FILD" in the search feature at the top of the site (second button from left) and go from there. There's tons of hits.