Recently started working at an HVAC company doing reception- what to ask customers to best help techs know what to do??

I started working at a new company about two weeks ago, and I am usually the only person in the office here. We all only communicate through text, and most of my job is answering calls from customers, writing down what they need and sending that to the techs.

I am struggling with knowing what to ask on the phone when people come to me with issues, and providing inadequate information to the guys, alongside dealing with the poor management. Can anyone guide me through some basics and what is important to know if you’re going on a call?? (Especially with issues with their water or plumbing I have no idea what I’m meant to be figuring out) Thank you.