I like the Phil McKnight videos on guitar maintenance.
I think this looks like a truss rod (relief) adjustment is the the majority of what you will want, but you need to verify if I see it accurately given I am only looking at a few pictures. This video will help you identify what is in need of adjustment. Be sure to watch the whole thing. I believe the nut looks about right, and I’m guessing the saddle may be about right given string height at the body/neck joint.
For doing a truss rod adjustment, I like this video. Stew Mac is a well respected tool supplier for guitar stuff.
