The snooker bridge hand is a very important part of the game and in many cases not used correctly.
Place your hand firmly on the table make sure your palm of your hand is in contact with the cloth and spread your fingers apart.

Lift your thumb towards your forefinger making a solid v for the cue to run through. It’s most important to make sure the muscles in your hand don’t get in the way of your cue action and if it does you can adjust the height and angle in which your thumb touches your hand.

The most important part is adjusting the bridge to the shot being played and not adjust the butt height as most new players to the game do.
The most important thing is to keep the cue as flat as possible to the table and a fluent cue action.