When you got your first salary job, what did you know about the field you were getting yourself into? What gave you confidence in the workplace?

I literally knew nothing at all. I was hired to do computer networking with ZERO experience. Everything I learned was on-the-job, taught to me by a private consultant that was onsite. Once he taught me enough that I could fly on my own, he was able to branch off to other clients, and eventually even hired me to work at his company after I left the first one.