Ask HN: Advice for first days/weeks/months at first dev job?

So I just started my first development job a couple weeks ago (I've been paid to code before but never as my sole responsibility and never in a software company). I need to learn a new stack, other than JS and the base server language all the frameworks and tools are new. I need to learn the codebase. These things are going well, I think.

They know I'm junior and seem to know it's going to take a bit for me to spin up, but I was hoping HN could share advice for how to make my early days count for the most.