Career Advice About Anthropic

I've worked at meta and stripe but in april I'll be starting a new job at anthropic. At this point i feel comfortable spinning up on new things at large companies where onboarding lasts months and the first couple weeks are just listening to presentations, but anthropic is the smallest company i'll have worked for (~1000 people) and their onboarding plan is a little intimidating. They want me to merge 1-3 diffs in my first week and to be fully spun up after 30 days.

What should i do to really hit the ground running that this new job and start pushing code from the start. I'll be on the growth team which is something im comfortable with since i did growth at meta, so mainly just looking for advice on how to learn a new codebase and company that's much smaller than i'm used to.