How to test install flow?

Question

I did a test project following the steps described. Everything went well, but when I click on Test Install Flow button it gives me "Need Admin Permission! You do not have privilege to install this application. Please contact your domain admin or directly sign-up on application provider website."

What am I missing?

Added the printscreen:

Answer 1

Solved misteries. My google account was not set as admin for my domain.

Answer 2

Screenshot might help. Also, recommend watching videos about authorization in marketplace.

OpenID-based SSO & OAuth for Google Apps - http://www.youtube.com/watch?v=0L_dEOjhADQ

OAuth 2.0 for Identity and Data Access - http://www.youtube.com/watch?v=YLHyeSuBspI