# Page Not Found

The URL `help-guides/building-a-user-interface/the-basics` does not exist.

You might be looking for one of these pages:
- [Introduction to testing and debugging](https://manual.bubble.io/help-guides/maintaining-an-application/testing-and-debugging/the-basics.md)
- [The Basics (Legacy)](https://manual.bubble.io/help-guides/design/responsive-design/legacy-articles/the-basics.md)
- [The database](https://manual.bubble.io/help-guides/data/the-database.md)
- [Sub-apps](https://manual.bubble.io/help-guides/infrastructure/sub-apps.md)
- [Web app](https://manual.bubble.io/help-guides/publishing-your-app/web-app.md)

## How to find the correct page

1. **Browse the full index**: [/sitemap.md](https://manual.bubble.io/sitemap.md) - Complete documentation index
2. **View the full content**: [/llms-full.txt](https://manual.bubble.io/llms-full.txt) - Full content export

## Tips for requesting documentation

- For markdown responses, append `.md` to URLs (e.g., `/help-guides/maintaining-an-application/testing-and-debugging/the-basics.md`)
- Use `Accept: text/markdown` header for content negotiation