How do I get UE4 Mannequin in FBX?

Create a new third person project from the Epic Launcher. Start the editor and find the Mannequin’s mesh. You can right click the mesh then do “Asset Actions -> Export” to a location of your choice. The default export options work for Blender 2.80

Do you provide paid support for the script?

Only limited support is provided in the form of community posts and publicly available instructional videos.

At this time there is no paid or advanced support to address individual user issues or customization. But it might be provided in the future.

Can you tell me how to do Animation? How do I use the rig?

I am not an animator or a rigger. I can not instruct you in how to animate or create new rigs. Uefy Script will let you use Blender 2.8’s rigify system with Unreal Engine by changing its default export.

But learning how to use Rigify or Blender is not something I can help you with. Please refer to documentation for Blender and Rigify.