The first one is called the Continental grip(pictures 1-3). Place your hand in a way such that the base knuckle of the index finger is right on the first bevel. Making strokes with the continental grip actually allows the forearm and the wrist to function smoothly. This grip is used for when you serve the ball and for quick volleys and strokes near the net. Striking the ball is all about timing with this grip. Putting spin to the ball is almost impossible. This is always used to make quick returns and defensive strokes.
The second grip is called the Eastern Forehand grip(pictures 4-6). First you need to place your hand in such a way that the base knuckle of the index finger is right on the second bevel. The forehand grip is one of the most comfortable grips to learn because it allows the player to get a proper brush and feel effect on the ball. Also when you want to switch to a different grip it is fast and easy. On the other hand this is not the most comfortable grip for higher shots.
The last grip is called the Two Handed Backhand grip(pictures 7-9). You hold the racquet with your right hand using regular Continental grip, then placing the left hand above the hand, holding it in a left-handed Semi-Western Forehand grip. Shoulder strength is the major way to use the strength and direct the ball towards the court. It is also good on low balls as the extra hand can add punch to the strokes. For this grip more effort to direct the ball is needed as the hip rotation is put into action.