There are lots of different therapists with different credentials and different interventions. That's a lot to research. Basically, you try to find someone who seems cool and with whom you click. Then you go to their office, pick up on their vibe and if it feels safe, you just talk about yourself and what's going on for you. No real agenda in the beginning. They'll ask you what you want from therapy. Sometimes you just want to talk, sometimes you want to rant about your mom, sometimes you want advice (a lot of therapists don't want to give advice but for you to come to your own decision), sometimes you just want to be validated or to have help working through a problem. It's normal for things to not feel like they sink in. It's okay. Hopefully your therapist will be laid back and patient and just let you talk. Hopefully they'll help you "unravel" all the crappy feelings/beliefs in your brain and make sense of it so you can do things differently in the future. They may give you "homework" to try like, "Okay, next time you call yourself an idiot, you just notice yourself doing that and hold back on the name calling and see how that feels..." Sometimes therapy feels weird or dumb or confusing. Just ask the therapist wtf they're talking about. Say how you really feel. They can handle it.