One of the first tasks for an engineer in a new company is to setup their environment.
Your goal is not to setup your environment
Your goal is to do something that the environment setup enables, e.g. make a copy or color change
Abstraction is essential when you’re working in a large codebase. Don't try to understand everything you come across: there will surely be a guide or script that you'll blindly follow, and that's ok. Keep your focus on completing the setup so you can make progress.
If you get blocked (you probably will...), forecast ahead what's coming and check if there's something else you can do in parallel.