How to add additional documentation and examples to an openapi spec generated with crnk-gen-openapi?

Question

I am generating the openapi spec of my spring-boot project with crnk-gen-openapi. This process works.

Now I want to add detailed documentation to the requests and examples with valid values. I did this in the past with springfox, so I assume it should be possible, but unfortunately neither the documentation nor an extended web search yielded a result.

Any hint is welcome.