The universal grip for serve, volley and slice: index knuckle on bevel 2, held like a hammer. In padel it is the only grip you really need.
Your grip sets the angle of the racket face at contact, which makes it the first fork in the road on every shot rather than a detail. The handle is an octagon; its eight edges are called bevels and act as reference points. Put the knuckle of your index finger on bevel 2 and you are holding continental — as if you were driving a nail into a wall with the racket's edge. The classic beginner error is playing everything with your usual forehand grip: the face then sits wrong on the backhand volley, and your serve stays flat with no spin. At the net there is simply no time to change grips, and in padel, with even shorter reaction times, there is none at all — which is why continental covers both wings there. One thing that gets lost: for a baseline forehand it is the weaker choice. Semi-western on bevel 4 produces far more topspin.