How to read the results
Each check comes back as passed, to improve or to fix. “To fix” is something missing or broken, such as a page that tells Google not to list it. “To improve” is something present but worth a second look, such as a title too long to fit. A few checks are optional and never count against the page.
“Do these first” puts the problems in order of how much they matter, each with why it matters and where the fix is explained. Every check carries a label: Google guideline, good practice, or new. The lengths we mention for titles and descriptions are guides, not limits set by Google, and the score is our own formula.
The audit looks at one page as it is served right now. It does not crawl the rest of your site, measure rankings or count links from other sites. Fix what it lists, run it again to confirm, then move to the next page. The On-Page SEO series and the Technical SEO series explain the reasons behind each check.