A couple of things....
Successful "managers" are leaders and coaches, NOT managers. There is a big difference. See if there is someone already in a leadership role that you respect at your company, and ask if they would mentor you, AND take some classes on what it takes to be a successful leader. There are hundereds if not thousands of books and theories on the subject. There is no right way. Find a style that suits you and your personality.
Second....Don't ask the "hiring manager" shit, unless they are the person already in that role, or they supervise that role. Someone from HR won't have a clue as to what the job "really" entails.
Ask other engineering managers at your company what the expectations are for them, and also ask how they are supported. This second bit is VERY important. A lot of firms apply the Peter Principle in selecting managers. This is doomed to failure. And for you, more so than the company. Heres how it works (or doesn't work for that matter).
"Lordxizor is a great process engineer...I'll bet he'd make a great manager."
Then once you are promoted they don't support you or give you the tools necessary to do your job. There is no training, no clear direction, no setting of expectations, no feedback, no follow-up, and no one has given you permission to make decisions as a manager, or told you what the parameters of your decision making authority even are. Basically, they have taken a productive, effective employee, and turned them into a hapless, and helpless manager. No thanks. So find out what support you'll get.
Lastly, ask your boss to guarantee you a parachute in the event that either you don't like the experience, or they don't like you as a manager for some reason. Be honest, and explain to him that considering the fact that you've never been a manager before, that you want to know that if it doesn't work out in six or 12 months or so, that you can take your old job back. When I worked as a labor lawyer I saw dozens of instances where a company took a very highly valued employee and promoted them with little or no support, and when the person fell on their face (and they always did in an unsupported environment), they wanted to take them out and shoot them in the face with a bazooka, which is just crazy. Tell your boss that in return for that option, that what he'll get is you'll do everything you can to immerse yourself in your new role, and will bust your ass to be successful. He SHOULD respect the hell out of that. If he agrees, ask him if HR will put that in writing. They may not, because they might feel that would constitue a guaranteed contract for future employment, but a GOOD and savvy HR person should be able to word it to protect both you and the company.
Good luck!