Ok, I'm in the process of doing this myself (started a new position after 12 years at my last job just over a month ago.) I take the approach that I always like

Ok, I'm in the process of doing this myself (started a new position after 12 years at my last job just over a month ago.) I take the approach that I always liked with people who I helped mentor at my last job: Just dig in on each new task, try and figure things out and when you get stuck, outline what you did/figured out, what you think maybe the next step is, and ask some clarifying questions before you get completely in the weeds. Take some notes so you don't need to ask THAT question again. You'll get up to speed reasonably quick, won't flail too much, and generally be respectful of other's time. Remember, you're new and it's ok to be clueless at the start. Just try and use each new thing you do to accumulate clue and you'll be fine.