Data Categories are hierarchical classification of articles that are controlled by the system administrator. Articles are tagged to Data Categories in a way that is similar to tagging a blog post with keywords.
Resource:
Knowledge Data Categories Best Practices - Knowledge Article - https://help.salesforce.com/articleView?id=000338764&type=1&mode=1
In addition to writing Knowledge Articles individually, you can also mass import them. In this lesson I walk through the process of importing Knowledge Articles into your Salesforce instance.
In this introductory lesson I introduce you to Salesforce Communities.
We start the process of creating a Salesforce Community in your org. We leverage Lightning Community Templates as well.