Hi Dinesh, 
You can just enter your email and request a login link. Click on the link from the email and that's it.
AdocateHub currently has some bugs (e.g. I do not see challenges at the Home page and have to go to the Challenges tab instead), they are working to solve it now.

For others - here's the link to the AdvocateHub mobile app, which you can use to log in to Global Masters from your mobile:
Android 
App Store