Compile Unreal Lightmass

Hi, I keep trying to build my lighting but it fails because it can’t kick off Swarm. It tells me to compile my UnrealLightmass. I know that’s in Visual Studio, but I can’t find Lightmass. If I search it comes back with no results. Do I need to download something extra for the Visual Studio or make some tweaks? How do I find UnrealLightmass? Thanks!