Today I noticed the outer layer of the skylight is broken. It was probably broken by a golf ball. This has happened before—glass got broken and no one took responsibility, so I just had to chalk it up to bad luck. I know nothing about this kind of thing, so I'm checking whether anyone handy on the forum has advice. I'm also searching for solutions myself. Thanks.
First, I don't even know when it broke—maybe it's been a while. Could rain during that time cause leaking or even mold? Inside the room, I don't see any signs of water leakage.
Then, how should it be repaired? Is replacing just the outer layer enough? Should I hire someone or DIY it?

Let me first go over the home insurance policy to see whether skylights are covered.