In a large company, you should expect a more formal onboarding process. However, don’t let this be an excuse to move slowly. Your goal is (still) to set up your environment and land code within a week.
Big companies will have many teams which may have slightly competing priorities. That means you need to invest in relationships and understand how the work connects between teams. Disperse and collect knowledge from around the company.
Spend some time understanding the unique terminology and culture of the company. Companies like Amazon, Meta, Google, Microsoft are large enough that they have their own set of acronyms, languages, and cultures!