How to use merge hint in Oracle?

Can you please explain, in simple terms, how one would go about utilizing the merge hint in Oracle? I'm a bit of a novice when it comes to database optimization and I'm trying to wrap my head around the concept of hints and how they can be Leveraged to improve query performance. Specifically, I'm curious about the merge hint and how it can be applied to optimize the execution of my SQL statements. Any tips or best practices you can share would be greatly appreciated.