How to export vertex animation to unity?

I created this shape keys animation(using vertex groups), and I want to export in into unity. Id does not work as i supposed, when I follow the tutorial about exporting to unity It works different. I haven’t found any description about exporting animation like this to unity. Can you help me with doing this? My animation:
0 frame

20 frame

Please note that I’m new to blender and unity so tell me if I made some stupid mistakes.