Search engines have a 4 steps process for their operation:
1.    Crawling the Web: search engines run automatic programs, called “bots”,” spiders or crawlers. They follow the hyperlinks from one page to another.
2.    Indexing Documents: once the document has been crawled, it might get indexed and stored in the search engines database. There are different factors that influence if a document will be indexed and how fast.
3.    Processing Queries: When the users request information, the search engines retrieves its index all the documents that match the query. A match is determined if the terms or phrase is found on the page in the manner specified by the user.
4.    Ranking Results: once search engines determines the documents, the engine’s algorithm runs calculations to determine which document is more relevant and should rank on top the search results.