docs(demo): add a walkthrough

[JonZeolla]

Contributor Comments

This adds a walkthrough video to the getting started section.

Pull Request Checklist

Thank you for submitting a contribution!

Please address the following items:

• If you are adding a dependency, please explain how it was chosen.
• If manual testing is needed in order to validate the changes, provide a testing plan and the expected results.
• Validate that documentation is accurate and aligned to any project updates or additions.

[ai-coding-guardrails]

Nice work! 😎

I didn't find anything of concern

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