How to run github codebase

[frantisek-heca]

Summary

I have followed steps here https://github.com/vercel/next.js/blob/canary/contributing/core/developing.md
To the point of:
Start developing and watch for code changes: pnpm dev

Please, what to expect now? What url is working? localhost:3000 does nothing
What directory should I edit in the project and see changes?

Thanks a lot

Additional information

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Example

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