Networking Questions

I have a couple questions about networking if anyone could give me a little advice:

1) Are networking calls usually over the phone or in some sort of video meeting like MS Teams or Zoom?

2) When calling the banker, should I call the direct (work) number or mobile number?

3) How does the conversation usually start? Do I ask him/her to tell me about himself/his career? - I don't want it to feel like I'm interviewing him/her.

4) Are there any questions/topics you recommend bringing up from experience? - I am new to this and don't have many alumni in banking, so most of my connections will have no commonality with me.

Thanks for the help!