Apache iceberg and hive metastore ?

Hello, sir.

I'm passionate about new architectures, including the Data Lakehouse. Fortunately, I came across his project of "Local-Data-LakeHouse ".It's a good start for me, I'm testing it on my machine.

But I don't understand how you did exactly in the second layer for Iceberg and hive metastore.
Please, can you explain this step to me ?

Thank you in advance.