Ask HN: How to approach first days on a new job as a senior engineer?

I'm switching companies, onboarding a team in a senior position. I would like to approach my entrance in a more deliberate manner than I did on the past.

It's not a comprensive list, but I would like advice or resources on:

- effectively learning key information to hit the ground running - knowledge management (checklists? Diaries?) - causing a good impression - positioning myself for impact - balancing adapting to the team with not absorbing established bad patterns - balancing being the people with less business context with being in a position where I'm supposed to lead