So I just met my biological brother and i don't know how to start to get to know him?

I just found out that my biological father has nine other kids. I am 16 and the oldest but there are a boy and girl that are 15 Im trying to get to know. The girl (Im not giving out names) is never on Facebook, but my brother is. I've tried talking to him and he says he wants to get to know each other, but every time I try and ask him something he just seems really distant. I don't know what to do...Any advise?