1. You will receive a voucher / key like this: 828oqzcunt2ncl9ci
2. Log into your account (If you haven't account, you just need to register https://takefile.link/user_registration)
3. Make sure you are logged in, then open page: https://takefile.link/user_profile
4. Put your Premium key / Premium code in "Apply Premium Key" and click on "Apply"