Go through the below links to get understand about basic Cloud Computing concepts and Pivotal Cloud Foundry. Read in the same order, that will help you to avoid confusion. I am writing these posts in the point of developer view.
Note: If any of Pivotal Operator ready to share/post articles, please mention a comment. So, I will reach out to you.
For more additional information about latest changes related to pivotal, follow on Pivotal Blog.