Example tutorials on how to do these are here:
The Renaissance Tailor
Article by Phillip Schillawski
In doing this write-up I've also stumbled on a you-tube tutorial. I've not watched it, but look forward to doing so soon.
I worked mine up in ver à soie silk embroidery floss over a wood bead. After trying a few, I decided to add the yellow splendor silk ridges and pearl at the top as finishing touches. These buttons are going on my oft ignored, but never forgotten eggplant silk veste. Yes, the "eggplant" silk is closer to the color of these buttons than the image on the aforementioned blog post. The fabric detests being photographed. The yellow will tie into my butter yellow sottana which will be worn under the veste.
I'm fairly pleased, considering I'm new at this.