I said this in another thread but I'll say it again.

I've learned and relearned to play clawhammer at least three times in my life.

What have I learned?

The best way to learn is from a live human being. If you learn from a book, you'll sound like someone who learned from a book. (Been there.) That's NOT a criticism by the way.

There are a million ways to clawhammer. You can spend the week at Clifftop watching right hands and you'll not see the same thing twice. These million different ways produce a million different sounds. NONE of them are WRONG.

So, learn from a live human being who has the sound you want to produce on the banjo.

BE WARNED that the devil is in the details.

Any player you ask will say something like "It's easy, all you do is...." S/he can then quickly show you the basic gross motions. You can probably pick them up just as quickly.

However....

Every tiny little thing makes a difference in clawhammer. The finger you use (index, middle, other), the angle at which the finger meets the string, the part of the finger which contacts the string (tip of nail, middle of nail, tip of finger, other), the number of fingers which make the brush, the strings brushed, the relation of the thumb to the 5th string (avoids, plucks, rests on, digs behind, other), etc., etc., etc.

The resulting sound will be a function of every one of these variables. Learning/figuring these out is where things get tricky. Accomplished banjo players aren't always (sometimes never) aware of exactly what they're doing. They find it hard to explain and difficult to demonstrate. You can ask them to slow down, but playing slow and playing a tempo are two very different things. You have to be persistent (not to say nagging) and watch and listening very carefully.

These subtle things can take a very long time to get "right." You'll know it's right when it sounds right. If it sounds right, it is right.

The last time I learned, for example, I spent hours just hitting the 5th string with the thumb until it felt right and sounded right.