Step 1: Tools needed
A small whittling knife or a chip knife is the best suited for the carving. But any small sharp knife will do the job. And a bigger knife is needed to split the wood into the 4 pieces needed.
I use my hand forged knifes and a pull saw.
If you don't have a suitable knife already I recoment you buy a pfeil or a flexcut I have used both brands and they a both very good. And they are available many places online.