Thank You all.Finally, I am able to link google app engine and odk aggregate.Now I could exchange blank and fill up form with other enumerators with the help of our IT team.I will share my experience shortly.Special thank
Narendra and A N M AL IMRAN, who help me enormously.
When I was trying to link the app engine with aggregate I had chosen the USA server rather than choosing the South Asia server.for that my app was not working.So I had created others project in Google cloud platform then choose the right server.Then it worked by following the above youtube's instruction. one thing was interesting that for every installation of aggregate through Gmail I got different token number. Hope so it will help other to understand the setup.
Thanks, I will try to make clear things as much as i can in my videos.