Hey downbutnotout.
Personally, I would email and ask directly. Something like this: "Good morning Professor/Dr. (whatever their title is) followed by last name. My name is X and I'm currently a 1st year student studying Y. I met with Mr/Ms Z, the campus counselor a few days ago and he/she referred me to you regarding a possible mentorship. I understand that you're busy, but if you have the time, then I would appreciate this opportunity very much. Thank you in advance for considering my request."
Usually, professors are more than willing to be mentors because they love passing their knowledge and experiences onto students. Good luck!
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Don't settle for someone who doesn't see your worth.