SEO Pros: Help me understand how to kick off my Keyword Research.

I'm new to the SEO game but not new to hustling in general. I'm curious what I need to think about to jump start my keyword research game. I'm assuming there are some tools that are good for this. I heard about SEM rush but the name implies search engine marketing so I wasn't sure. What are the tools to use (free or paid). I generally like to take an organic approach (trying to search stuff up myself on Google, but I wasn't sure what to even search for).