Update contributing.md to link to walkthrough video. (#34299)

Hopefully this helps folks contribute 😄

contributing.md

@@ -1,10 +1,12 @@
 # Contributing to Next.js
 
-Read about our [Commitment to Open Source](https://vercel.com/oss). To
-contribute to [our examples](examples), please see **[Adding
-examples](#adding-examples)** below.
+[Watch the 40-minute walkthrough video on how to contribute to Next.js.](https://www.youtube.com/watch?v=cuoNzXFLitc)
 
-Before jumping into a PR be sure to search [existing PRs](https://github.com/vercel/next.js/pulls) or [issues](https://github.com/vercel/next.js/issues) for an open or closed item that relates to your submission.
+---
+
+- Read about our [Commitment to Open Source](https://vercel.com/oss).
+- To contribute to [our examples](examples), please see [Adding examples](#adding-examples) below.
+- Before jumping into a PR be sure to search [existing PRs](https://github.com/vercel/next.js/pulls) or [issues](https://github.com/vercel/next.js/issues) for an open or closed item that relates to your submission.
 
 ## Developing