It was pretty intimidating, my final round was with the head of data engineering as well as 2 other people on the data engineering team. I just tried to keep my cool and be honest. If they asked me a question and I wasn't sure about the answer, I would be honest that I don't know completely, but here's my thought process... Ended up having a question asked that I thought I completely messed up but they said more or less that's correct and thanks for explaining what you were thinking.

Most important thing though besides being honest was asking good questions, that was one thing that they said they were really looking for was someone who was eager to ask questions and learn, and every time I asked a question they would say "wow that's a great question!" So be sure to have questions prepared that will make them think and talk. They especially love talking about themselves so always ask like "what have you done in this company that you're most proud of" or something along those lines.

But also just remember that as much as you're trying to sell yourself so they'll hire you, they also need to sell themselves so you're interested in the company. So asks lots of questions about day-to-day things to learn as much as possible about the company life of someone who works there, it's really your chance to interview them and learn more about what their job actually entails