So your telling me that I am basically going to go searching through threads of 100's of literary agents, then send a literary agent who I don't know a "query letter" or advertisement of my book? then hope they like it and they will try to sell to a publisher?
Actually, I just noticed on the Welcome New Members thread that you are writing an autobiography. Therefore, as Siri Kirpal said, you must follow a slightly different process for non-fiction by submitting a proposal including you platform (who you are and how the kids know you i.e., social media followers).
Yes. We all have to play by these same rules. Unless you know someone in the publishing business and can catapult right over these submission requirements. For example, if you know a published author, they may be willing to say a good word on your behalf to their agent, who might take a look at your writing sample as a favor. Otherwise, you have to do it the old fashioned way as outlined above.
Here's the kicker: agents like for you to personalize your query letter, much like you would tailor your resume for a specific job application. They want to know why you think they would be a good fit for your work. You can figure this out based on the genres they represent and any other information you can glean from online interviews they've given, writing conventions you saw them speak at, etc. Then, if you get an agent who believes in your work enough to want to represent you (from the several thousand queries they receive each year), that agent then begins submitting your work to editors at publishing houses much the same way as you queried the agent. So, having an agent doesn't automatically mean you sold your book.
Best of luck!