Learning SEO

I’d like to learn seo from the very beginning because I don’t have templates and lack in knowing short cuts. I have access to the work site so could learn on that. Can anyone recommend the best way to learn step by step in a methodical way? I’ve done searches and there’s Google, moz etc doing free courses but actually I’m looking at a methodical way and the courses just send me to different areas all the time so I get stuck with what I should do first and how to follow. Thanks I’m advance