To understand seo you need to be aware of the architecture of search engines. They all contain the following main components:
Spider - a browser-like program that downloads web pages.
Crawler – a program that automatically follows all of the links on each web page.
Indexer - a program that analyzes web pages downloaded by the spider and the crawler.
Database– storage for downloaded and processed pages.
Results engine – extracts search results from the database.
Web server – a server that is responsible for interaction between the user and other search engine components.
Specific implementations of search mechanisms may differ. For example, the Spider+Crawler+Indexer component group might be implemented as a single program that downloads web pages, analyzes them and then uses their links to find new resources. Buy traffic for your website and make more sales! However, the components listed are inherent to all search engines and the seo tools principles are the same.