How do I ask for an informational chat? (Madison)

I sent 9 messages on a professional network and got two replies. Any experience at all would help. I want advice, not a job directly. How do you phrase the request?

Follow up with a thank-you and a short update. One of my chats led to a referral a month later.

I wrote three short lines: who I am, why them and a small ask for fifteen minutes. About one in four said yes.