'create service' documentation

Can someone please clarify the ‘docker create service’ documentation at https://docs.docker.com/engine/reference/commandline/service_create/#add-bind-mounts-or-volumes. How does the COMMAND interoperate with the CMD and ENTRYPOINT sections of images? The intended pattern seems to be an execution chain with a mutable environment, but how the chain is setup and the environment is modified is unclear to me.

There may be other issues - it’s only possible to register a down-vote on the documentation pages. The ability to add a comment might help to improve the overall quality.