Technical SEO refers to the technical aspects of a website that can affect its visibility and ranking in search engine results. The following are some of the technical SEO basics:

1. Crawlability: Ensure that search engines can easily crawl and index the website, by providing a sitemap and robots.txt file, and by fixing broken links and other crawl errors.
2. Mobile-friendliness: Make sure that the website is optimized for mobile devices, by using a responsive design or mobile-specific URLs.
3. Page speed: Optimize the page speed of the website, by minifying code, compressing images and using a content delivery network (CDN).
4. URL structure: Use a clear and consistent URL structure, that is easy for both users and search engines to understand.
5. Header tags: Use header tags (H1, H2, H3, etc.) to organize and structure the content on the website, making it easier for both users and search engines to understand the content of the webpage.
6. Alt tags: Use alt tags to describe images on the website, which can help to improve the accessibility of the website and also provide additional context to search engines.
7. XML Sitemap: Create an XML sitemap and submit it to search engines, this will make it easier for search engines to discover and index new pages on the website.
8. Meta tags: Use meta tags to provide additional information about the website, such as the page title, meta description, and keywords.
9. Structured Data: Use structured data (Schema.org) to provide additional information about the content on the website, which can help to improve the visibility of the website in search results.

In summary, technical SEO refers to the technical aspects of a website that can affect its visibility and ranking in search engine results. Technical SEO basics are the fundamental things to set up a website for better visibility and ranking, like crawlability, mobile-friendliness, page speed, URL structure, header tags, alt tags, XML sitemap, meta tags, and structured data.