Clarify instructions
Clarify instructions

* Eliminate unnecessary port change.
* Clarify code change and breakpoint location.
docker/docker.github.io,thaJeztah/docker.github.io,docker/docker.github.io,docker/docker.github.io,docker/docker.github.io,docker/docker.github.io,thaJeztah/docker.github.io,thaJeztah/docker.github.io,thaJeztah/docker.github.io,thaJeztah/docker.github.io