I really like this series of 6 videos from Rand Fishkin, an industry-recognized expert in SEO, that explains the fundamentals, with beginners in mind.
1. SEO Strategy
2. Keyword Research
https://moz.com/blog/one-hour-seo-guide-part-2-keyword-research
3. Searcher Satisfaction
https://moz.com/blog/one-hour-guide-to-seo-searcher-satisfaction
4. Keyword Targeting & On-Page Optimization
https://moz.com/blog/one-hour-guide-to-seo-keyword-targeting-on-page-optimization