First you divide SEO in 2, on page and off page.
On page SEO is optimizing your pages following the important steps of on page optimization. You need on page SEO to become more discoverable. There are many guides here on how to perform on page seo on your web pages.
Here are some guides that might be helpful for you to understand the fundamentals/basics.
https://www.blackhatworld.com/seo/a-complete-idiots-guide-to-on-page-optimizations-for-your-website-newbie-guide.594529/
https://www.blackhatworld.com/seo/easy-as-fuck-on-page-seo-guide-checklist.1025148/
https://www.blackhatworld.com/seo/on-page-seo-an-actionable-guide-for-2018-19.1078726/
Off page SEO is link building, press release, guest posting and etc.. Basically it’s whatever you do outside of your website.
Since everyone has a different off page strategy, my advice would be stay away from spammy, unrelated, cheap links. Rather, invest your time on building more authority links and creating backlinks on websites related to your niche.
There are many more detailed guides written by our members here in BHW. A quick search using the BHW search bar will lead you to those guides.