1. Click on Download. A Window with different surveys will pop up.
2. Choose a survey and fill it out. Most of the time it's a survey where you just have to enter some information.
(make it look valid or the file won't unlock).
Some countries only have MobileCellphone surveys. You can fill them out by just typing your mobile number and sending an SMS that cost less than a dollar and receiving the SMS with your code to complete the survey.
3. After you have filled out the survey your download will automatically unlock.