Just like Rome was not built in a day similarly you can't become an SEO expert in a week or Month. A lot goes into becoming an SEO expert. You have to learn the basics.

You need to learn What is a search Engine? How Does a Search Engine Work? What are the Google Algortihms? What is keyword research?

Which tools are used by SEO people for Keyword Analysis. Once your basics are clear you can create your own Free blog or website and start learning SEO on your own.

You can refer the website called "The Creative Keeda" and check out their Digital Marketing section. It its one of the best guide to SEO for beginners.