1. You will receive a premium key like this: 3492eystidam0szzzz

2. Create an account or login to your Kenfiles account: http://kenfiles.com/?op=login

3. Make sure you are logged in, then open redeem voucher page: http://kenfiles.com/?op=active_voucher

4. Enter premium key in field with that description "Voucher Code:" and click "Active Now" button