Here is instruction to activate your Katfile Premium Key
1. You will receive a Premium key / Premium code like this: 1220s5e5cbo381XXXXX
2. Login to your Katfile account (You should register your own account, if you dont have it, https://katfile.com/)
3. Go to Profile page. (http://katfile.com/?op=my_account).
4. Find Apply Premium Key field
5. Put your key here, then apply it.