Conducting a patent search is a complicated process. Please see this tutorial from the US Patent and Trademark Office on how to conduct a preliminary US Patent search. Use Chrome, Safari, or Edge; it doesn't work well in Firefox.
The USPTO also has new, shorter videos on topics specific to patent searching.
The Lens.org has tutorials on searching for patents in their database.
The World Intellectual Property Organization (WIPO) has a very comprehensive 8 hour e-Tutorial on how to use and exploit patent information. The tutorial is interactive and self-paced, however it is only available at designated times and by registering for an account.
How to Search for Patents
UCF Libraries
This video explains patent classification systems and demonstrates how to conduct a patent search step-by-step using the free global patent database, Espacenet. Video written and created by Karli Mair in collaboration with Patent Librarian Hal Mendelson.