[storn42]

The games difficulty scale and charts are designed around using the spread playstyle, where you use 2 fingers on each hand to play 2 buttons each. That is what is largely considered the optimal way to play. there are plenty of other play styles out there, like using 3 fingers on 1 and and 1 on the other, or just using both index fingers, but the majority play with spread. If you dont care about optimal play, just use whatever style you have fun with.