It is a fact of learning that all education is self-education. Although others can facilitate learning, nobody can teach you anything--they can only inspire you to teach yourself. That means if you want to learn search engine optimization (SEO), you'll have to take matters into your own hands.
SEO for Beginners
There's no better resource I've found as a starting place to learn SEO than The Beginner's Guide to SEO from Moz. It's free, and it starts out answering the most basic questions like "What is SEO?" Read the entire guide once and you'll know more than the people sending you those spam SEO emails every day. Read it twice and you'll know more than a lot of the so-called SEO experts. If you only have the time to do one thing to learn SEO, reading the Moz guide is it.
Moving Toward Expert Level SEO
The depth of experience for many SEO experts goes something like this: "Optimize your title tags, make sure your site loads quickly, and then write a lot of blog posts, ask for some links back to your site, and you'll see your site start ranking better." Even if these SEO experts tell you it takes more than this and gives you the impression they're doing more, this is often the extent of the services they provide. If you only have beginner level knowledge of SEO this will sound reasonable and you'll have no reason to expect anything more until you fail to get results. By investing a few hours a month, you can move toward becoming a true SEO expert yourself and then you'll have the knowledge to know what those you hire to do SEO for you should be doing, and you can better gauge their readiness before hiring them.
source: https://www.forbes.com/sites/joshsteimle/2015/09/18/how-to-teach-yourself-seo/#4b6426c473f5