1. You receive Premium key look like: 926nmow8q90sabep

2. You should be log in at https://pandafiles.com/login.html

(Please register a new PandaFiles account, if you don't have an account)

3. Access "My Account" to activate your Premium key: https://pandafiles.com/?op=my_account

4. Enter Premium key in field with description "Apply Premium Key" and click "Apply" button