I see what you mean, when looking into CHOPs it difficult to find a tutorial only about them. I think this is because they are usually used in a project to help get data to places and control things, but rarely is a project ever all CHOPs. So they are mingled into other workflows, unless you are just working with audio or doing some specific data massaging.
In Matthew Ragan’s [THP 494 / 598] classes there are some specific examples with audio, the Timer CHOP and more. https://matthewragan.com/teaching-resources/touchdesigner/
Also alltd.org is a huge repository of all the tutorials ever found about TD and there are about 135 with the tag ‘CHOPs’, so perhaps search through there for the topics that interest you. http://alltd.org/tag/chops/