First stage started off as my team interviewed me and decided they would be ok having me as their manager. People started acting differently (too many jokes!) even though nothing was really different.
Second stage started when my manager marked me as the manager in the personnel systems and I got new rights to see / hear stuff. I learned that while being a tester I never had to do mundane clicking, that was pretty much core my my new managerial responsibilities. Accepting people's hour reports (only if they insist doing them, we have an automated way for it too), people's vacations and expense reports.
Third stage started when I started finding the work undone while the engineering manager position was open. The recruitment process with all its steps. Supporting new people joining the organization. Saying goodbye to people when we agree the person and the work are not right for each other. Rewarding existing people and working towards their fair pay.
I found an Engineering Managers' Slack group, and have been fascinated with the types of things Engineering Managers talk about. A lot of this stuff is still things I was doing while identifying as "individual contributor".
I've found two weird powers I now have been trusted with: terminating someone's contract is just as easy in the systems than accepting hour reports (and there is something really alarming in that). And as a manager, I have access to proposing bonuses without having to do all the legwork I used to do to get people rewarded.
Officially one month into my new role and now one month on vacation. We'll see what the autumn brings.