Fewer than 2 or 3 people I have worked with have had a correct grip. A correct grip is one that fits you and your body. Everything in golf is done with your hands so having a correct grip is critical.
Bend forward and let your arms hang. This is how your left arm should be at impact. Your left hand grips where it naturally hangs so that momentum squares the face at impact.
The shaft fits diagonally in your fingers and the heel pad folds on top of the grip. The thumb is slightly to the side and here's why.
The right hand squares to incoming force. In the golf swing, it squares to the incoming force of the ground. Here is what your right hand fingers should do to let the face square at impact.