Having said that (and if you're still going to go for it), I'll try to give you some pointers.
1. Being a good engineering manager means having a good framework for getting things done. You probably have something like this already but as a manager, you have to be disciplined about keeping your team happy and productive, as well as knowing what everyone is working on at all times.
2. Be able to demonstrate how you think strategically and not just tactically (e.g. tactical: we're going to use MySQL because we have a hard schema, strategic: we're training engineers on the AWS tech stack because we have (or want) to move our organization in that direction for financial reasons).
3. Value "output over activity". Andy Grove's High Output Management is a godsend that explains this concept very well, but for the interview, demonstrate that you know the difference between people flapping their wings vs moving the needle forward.
4. Be able to speak about the difference between leadership vs management. Leadership is getting people to follow you while management is having people work for you. Management also means understanding the schedule, building a roadmap, and working with other groups to influence or lead important initiatives.
5. Helping ICs manage performance, motivate and incentivize good work, providing mentoring and guidance including career advice, rooting out low performers and managing them out. This is the hard, potentially unpleasant part of the job, and you'll need to demonstrate an understanding and willingness to do this (no one else will do this for you, this is the manager's job). Critical; since you don't seem to have experience here, you better brush up on this stuff most.
6. You job is also to understand current technology trends and be up to speed on the code, the process on the team, and the ways that things could be improved. Understand iterative process improvement and talk about how you've done this in the past.
There's lots more but this should hopefully cover the big important stuff.
All the best to you!