To become a registered customer, you just have to click in LOG-IN/SIGN-IN, write your email address in the field below "Create a customer account?" and click in the green button "CONTINUE". After that, fulfill the form with all the required info.
Do not forget to set a safe password (it's mandatory to choose a password with 8 or more characters including capital letters and lower cases with numbers).
When you finish fulfilling the form, click in the green button "FINISH".