The three ways your hands connect on the club: overlap (little finger resting on top), interlock (fingers hooked together) and the ten-finger or baseball grip.
The grip is your only connection to the club, and it decides where the clubface points before you even start the swing. Which of the three styles you pick matters surprisingly little — overlap, interlock and the ten-finger grip all do the same job: make both hands work as one unit. Take whichever feels stable and stops your hands from pulling apart. Three other things matter far more. First, the club sits in your fingers, not in your palm; in the palm it locks the wrists and costs you both distance and feel. Second, the grip is neutral: looking down at address, you should see two or three knuckles on your lead hand. Seeing fewer is a quiet contributor to the slice. Third, hold it lightly — tense forearms brake exactly the acceleration you were hoping to buy by squeezing harder.