As a line manager a huge mistake you could make (especially if you’re joining a new team) is not being technical enough.
You may not write code anymore, but you are expected to know the system very thoroughly, otherwise you’ll be perceived as a glorified babysitter.
As a new manager it’s very easy to fall into the trap of not doing any technical work because you’re a big boy now playing in the big boy league, but this will 100% hurt you.
You need to stay on top of everything your reports are doing. Give them their space but always ask hard questions and dig deep.
Frame it like this: if this report were to quit today, are you able to step in and complete their project? I’m not saying it’s something a manager is supposed to do, but that ultimately YOU are directly responsible for your reports’ work so you should be extremely familiar with it.