Just go, seriously go and walk up to whoever is in charge of whatever event you're at and say that you have a huge interest in the field and you'd love to learn

Just go, seriously go and walk up to whoever is in charge of whatever event you're at and say that you have a huge interest in the field and you'd love to learn more, people that host those type of events usually really love enthusiastic people. As a side note, don't mention just wanting a friend, people don't respond well to desperation, so don't act that way and you'll have an easier time making new friends.