The bow is held by the right hand, at the frog, the black endpiece of the bow. Bowhand is not a strict requirement that must be conformed to exactly. Obviously, as one plays and learns from their experience, they will develope a more personalized bowhand.
However, the bowhand remains mostly the same for each player. The thumb is placed on the gap between the bowgrip, the rubber grip on the bottom portion of the bow and the frog.
The index finger is placed ahead of the thumb, near the middle of the bowgrip. The middle finger is positioned roughly on the line between the end of the frog and the start of the bow hair. The ring finger is placed in the middle of the frog. Finally, the pinky is placed on the side of the screw. The bow should also be held with a straight wrist.