Moving the energy in a Figure 8 pattern can be done, literally, in any way you wish - experiment to see which 'feels' as if it's moving the energy most:
try different fingers,
try all fingers,
try finger tips,
try palms of hands
try the fingers or palm facing different directions
try different sizes, from tiny to big
try different directions, up and down, side to side, diagonal
try different distances
try various speeds of tracing
try different time lengths: from 5 seconds to 5 minutes
There are many variations and the 'secret' is to find the combo that moves the energy for you, that you feel you can 'connect' to feel the change.
The figure 8 is a healing symbol, the Tibetan sign for infinity. I don't know the science behind HOW it works, but I do KNOW it works .... I've used it on myself, clients and animals for decades with the most remarkable results in speeding the body's self healing ability e.g. on wounds, after surgery. If you look at my forehead, I had 12 stitches from top to bottom .... and the scar is super light, nobody every notices it!
Have fun with it, knowing that it's simplicity is deceptive, it can be a profoundly effective healing technique.