1. After you clicked on the download button it should show you a windows with surveys.
2. Choose one of the given surveys and complete it.
There are pretty easy surveys where you just have to register for free somewhere.
Most of suveys last about 1-2 minutes.
3. After you have filled out the survey downloas should unlock if you have entered valid information.
If not try again with another survey.
Not working? Try antoher survey.