It goes something like this example;
How to create sine-wave groove in ring geometry with extrudegeometry? - #6 by prisoner849
https://jsfiddle.net/prisoner849/8bw94cs3/
A variation of this:
BeginnerExample
// … step 05: modify a standard geometry
You can find the arrangement of the vertices there:
three.js/CylinderGeometry.js at 350f0a021943d6fa1d039a7c14c303653daa463f · mrdoob/three.js · GitHub
line 73 …