It is a deep and sometimes complex subject. I started with oratory1990 presets and I still use them as a starting point if there isn’t a preset on Headphones.com EQ Repository & Request Thread. The oratory1990 FAQ is a good place to start with how to use an EQ preset. I hope it is still up to date.
Once you’ve got some experience, you can really dive into the weeds at Tuning EQ to your personal HRTF.