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.