If you have a wood lathe, its very straightforward. There's a ton of different and cheaper woods you can practice on till you get it just right. I'm in the process of getting back into wood turning, but I've found that decent turning tools have skyrocketed in price.

The only tip I can give you is, drill the hole for the knot before you turn the handle. That way, its perfectly centered. Your lathe centre should fit in the hole just fine.