To enter your sponsor code, you must first create an account by clicking on (1) "Sign in" and (2) "Register now".
You will then just have to fill in the information fields and (3) enter your "Sponsor Code".
Finally, you will have to finalise your registration by (4) clicking on the "Register now" button.
Please note that the sponsor code must be entered when you register. It will not be possible to enter it later.