Traditional grip is not as common as matched grip and is generally used by jazz/swing drummers or in drumlines. I definitely think it’s worth learning.
First, make a relaxed “C” shape with your right hand. Your four fingers should be together.
Now, “live long and prosper”. Keeping your other fingers together (and still in the “C”), make a gap between your ring and middle fingers.
The stick should sit in between your thumb and index finger and rest on the nail groove of your ring finger. I should probably say here that, yeah, this grip will tear up your nail groove if you use it a lot. Sometimes I use band-aids or some kind of tape to protect it.
While using this grip, your thumb should be attached to your index finger’s top knuckle. The rest of your fingers should stay attached, like you’re trying to keep water inside your hand. Your right hand will be in matched grip.
When you drum with this grip, the wrist movement will be very similar to turning a doorknob. The wrist is not the driving force of the traditional stroke, though. Your thumb is what actually pushes the stroke through here.
This is a tricky grip that takes a lot of getting used to. Don’t get frustrated too easily, and remember that everyone has trouble with it in the beginning.