Hi Michael! I'm 25 and I lived in San Diego for around 5 years. When I started my journey to ditch my skinny-fat body for a more muscular one (a journey I am still on) I probably started out a lot like you. Don't hesitate to ask specific questions, there are a lot of helpful people here!
1) eat real food - more vegetables, moderate meat, moderate fruits, less grains, less sugar, less vegetable oils.
2) exercise - moderate intensity cardio, sprinting, heavy lifting, dedicated stretching and mobility.
3) live - relax, de-stress, meditate.
Disclaimer: I'm not professionally qualified to make any formal recommendations. I've just done my homework and I'm my own guinea pig. All of my data, unless otherwise cited, comes from a sample size of n=1 (me).