How to add new 'Content Type' or 'Content Item', how to add them to a 'Content Subscriber'?

Summary:

Content (required):

How to add new 'Content Type' or 'Content Item', how to add them to a 'Content Subscriber'? 

as Create & Edit buttons are dimmed?

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):