step 1. Try presets that have already been calibrated to some target for those specific headphones. There are hundreds to thousands of headphones included in the bigger preset collections.

step 2. tweak the EQ values by yourself by ear if you want to. There is no objectively best sound, so it comes down to your personal preference anyways, and you can't measure that in any practical way (and I'd say neither can the companies making expensive headphones, which is why there are hundreds of different headphones both cheap and expensive with different frequency responses and more getting made all the time)