Finishing a skylight removal

New homeowner here. I'm relatively handy, though I don't really enjoy construction work. A contractor wants 3800 to insulate (with foam) and fill in the skylight hole my ceiling that we had removed when they put on a new roof. I'm considering do it myself. Any advice? Do I need to remove the skylight framing first? Is it better to just pay the contractor? It'll need insulation and a largeish drywall patch.