Improve docs for getting started with Kustomize

We would like to have more entry-level tutorials as part of the Kustomize documentation, both to help users get started and to showcase best practices. Ideally these would include some video tutorials!

/help-wanted
/triage accepted
/kind documentation

Review the existing Kustomize documentation and current getting-started material first. Identify the gaps in entry-level tutorials and define a focused scope; done means the beginner guidance is published and the requested tutorial approach, including any video material, is addressed.

Written by the indexing model from the issue text.