Finger notation is important because you can use it to express fingering and understand methods players use to hit complicated patterns.
Use numbers 1 to 4 to express Index, Middle, Ring and Pinky fingers for the left hand, and use numbers 1 to 4 in brackets to express the same fingers, on the right hand. So for instance if you see “(1)” – that means “tap this note with your right hand index finger”. If you see “1234” – that means fret the notes in sequence with your left hand. Sometimes, fret notation, e.g. GRYBO is used instead of numbers. In addition, square brackets are used [like this] when referring to an anchored note.