TMT Associate interview - operating model question

Hi, I just had an interview for an associate position in the TMT team of one of the BBs. I was asked a question I've never heard or come across before and I really had no clue how to answer/structure it.

Interviewer: Could you a) walk me through an operating model you've built for a TMT company and b) run me through how you went about making projections

Me: *chats absolute shit*

I've never come across this before. How should you structure and answer this question?

Unsure if I will make it to the next round they said I will hear back soon, but I want to be better prepared if I make it to the second round.

Thank you.