There are lots of great resources on the internet to learn the basics of SEO.

Google has a great PDF at https://static.googleusercontent.com/media/www.google.com/en//webmasters/docs/search-engine-optimization-starter-guide.pdf. This getting started guide will give you the basics from their eyes.

Google also offers some online information on How Search Works and this can be found at https://www.google.com/insidesearch/howsearchworks/thestory/index.html.

The key is to make sure you are using current information from trusted sources. Outdated information can quickly lead you astray.

I publish a list of recent articles from trusted sources at https://www.diyseocourses.com/seo-articles-news/. This would be another good location to get up to date information from people and agencies you can trust.