Basic Bow Hold
Finger Placement. Your thumb should rest in the small curved part of the frog so that it touches both the stick and frog Your second finger goes over the stick and rests against the far side of the frog and is opposite the thumb Your first finger touches the stick between first and second knuckle and should be slightly away from your second finger. Your third finger passes over the stick and touches the far side of frog. The tip of your fourth finger goes almost on top of the stick, but presses against the near edge of the flat top of the stick.
Your palm should be higher than the stick. Your fingers should curve downwards towards stick You should have flexibility in the thumb and fingers so you can move the bow left and right, and up and down.
You can practice most of this with a large diameter ball writing
pen