Unable to setup UnrealEngine-FleX

Hello, I recently downloaded UnrealEngine-FleX-4.19.2, but I am having trouble setting it up. When I try to generate project files, I am told “ERROR: UnrealBuildTool Exception: Windows SDK v8.1 must be installed in order to build this target.”. Where can I find this SDK? I already have Windows 10 SDK (10.0.19041.0)