How do I tell someone I want to keep in contact when we barely know each other?

Hello everyone, it’s your favorite social inept here. So i met a guy in band who sits next to me, and he initiated conversation with me. The next few rehearsals we talked a little bit more, and I only know a few things about him. Now, we only have two more rehearsals, and I probably won’t see him again after. I want to tell him I want to keep in contact, but I don’t know if it’s too awkward or weird to ask that since we barely know each other. Also, I don’t even know how to do that