How to activate DDL.to Premium Voucher:
1. You will receive a DDL.to premium voucher like this: 79xxdlnd5774la
2. You should be log in : https://DDL.to/login.html
( If you haven't account at DDL.to, you just need to sign up: https://DDL.to/?op=registration )
3. Make sure you are logged in. Then access this link: https://DDL.to/?op=my_account
4. Put your voucher code in field "Apply Premium Key", and click on "Apply"