Large Skylight installation

Hello, I was inspired by the Yacht Vibes DIY van on youtube with a large skylight at the rear roof of a 3500 extended promaster. I bought the van and the skylight but there’s a roof rib/crossmember in the way. No idea how she installed that skylight or if it’s safe to remove or modify the rear crossmember/roof rib. Anyone know about large skylight installations?