Getting started with SEO

I have always found Reddit communities very supportive and helpful, so asking for advice. So I have started an agency and want to do my WordPress website SEO. Now, I have absolutely zero knowledge about SEO, but I wanna learn and do it myself for my Agency. Please note, - I have a technical background but have not done WordPress before. - Do I need to learn WordPress before doing SEO? - If you are a complete beginner how do you get started with SEO? - What tools should I buy, and what courses can I do? - My domain is just six months old. Also, kindly do not DM me; I do not wanna outsource my SEO; rather learn it and do it myself.