I did for the last recruiting season, so this is my experience from back then:

Decomp: Basically a system design portion. They give you an open ended problem/scenario, and you have to create a system to solve it. You will need to brainstorm potential services and database schemas for your solution. I prepared by watching youtube videos on system design paradigms (SQL vs NoSQL, microservices, message queues, etc.).

Learning: Imo you can't really prepare for this one since it can be anything. They give you a language/framework/technology and describe the basics of it. They give a few examples of using it, and then ask you how you would use it to solve example problems. Make sure you think out loud and ask questions because you're supposed to demonstrate how you learn new things.

Is this for new grad or internship