Squash is a fast game so we don’t have time to change grip from forehand to backhand. Therefore we use the same grip both sides.
One way of forming the grip is to visualise shaking hands with the racket. Alternately you can move your racket hand down the racket face and shaft to hold the grip.
For right-handers the ‘V’ between thumb and forefinger should be down the left side of the racket when held like this. For left-handers this is reversed with the ‘V’ being on the right hand side.
This enables you to prepare an open racket face on either side by rotating your forearm as shown. Ideally hold the grip in a central position on the handle.
There is a degree of flexibility allowable here but avoid extreme grips – they will do your game no good at all in the long run!