Talking about docker, it is a software technology which provides containers and an additional layer of abstraction and automation of operating-system-level virtualization on Windows and Linux.
Here are the best resources of Docker that I could find and this is very helpful if you are beginner:-
Apart from this, you could visit Docker Community to clear any doubts or ask questions, I have found it to be a great place to troubleshoot Docker related issues. You can also refer to the following video tutorial to learn Docker. .