Question on how to respond to a referral

Hi all,

I hope that you are doing well. I was lucky enough to connect with an alum of my school who is an MD at a BB. He was very nice and after I emailed him, he referred me to multiple people, one of whom already contacted me.

I'm a complete neophyte to this (no finance background but interest) so I was wondering:
1. I should thank him again, right? If I thank him, should I reply to everyone, or just to him?
2. Should I wait for the other people who haven't contacted me to reach out to me or should I reach out to them?
3. The first individual who said he's happy to talk to me said I should give him time - I'd like to have more time to study and prepare, since my friend told me that this would be analogous to an interview. What is an acceptable time frame to give?

Thanks so much!