Onboarding is arguably the most important part of your internship as it sets the foundation and tone for your entire software engineer internship.
Set up a 30 to 45 minute meeting with your intern manager (IM) ASAP, so they can explain the codebase to you at a high-level (i.e. a component level).
Make sure you have a recurring 1:1 meeting with your IM, which should be a weekly 30 minutes. Your IM should set this up for you, but in case they don't, you can work with them to set it up.
You will get 2-5 onboarding tasks to work on across the first ~2 weeks. The purpose of these is to familiarize yourself with the codebase.
Aim to put out your 1st diff by the end of Week 1. If you're doing this around the end of Week 2, you're really behind.
Ask a ton of questions and learn to ask high-quality questions. Don't be afraid of "over-asking" questions: If you're polite while asking questions and attaching great context to them, you will be fine no matter how many questions you ask.
Use Work Chat DMs to ask for help aggressively during this period as it's vital for you to become productive within the codebase very quickly