Making friends from scratch at 18

I recently got out of a relationship, where I halfway stopped prioritising working on my network

I got used to spending most days with my ex and his friends, and sleeping over at his moms place with him in his city. - especially thinking that the end goal was to move there

Now I’m sitting in my own city, really lonely from going to having people around to now not really

And I’m currently not studying, so I’m not really meeting many new people naturally

How do I fix this? And what’re some good places in Odense to make connections with people in this situation?