Beginner SEO Questions

Hi r/SEO

I am very new to SEO and am relaunching my website through Wix (it is a simple site that does not require much functionality). I have some questions regarding SEO best practices as I have not been able to find a conclusive answer to these questions online:

What is the start to finish process (at a high level) to writing SEO content?

When you write content optimized for SEO do you choose some keywords you wanna rank for and write all content around those or do you choose different keywords for different pieces of content?

I am not in a business that relies on organic traffic heavily as we are a very new tech startup (in other words, the keywords I could rank for are not very popular) how important is an SEO strategy to my specific business?

Thank you so much!