You need to create a free account first.
Go to your account. Once you are in your account you will see the link to “Premium Plan”.
You have two premium plans. One for agencies, developers or companies with various websites and another just for your website. Choose the one that works better for you. Company Plan is for developers who work for several websites or for an agency creating lots of websites or if you manage multiple domains.
Once you choose your plan and click “Subscribe” you will go to PayPal for final payment. Once the payment is done, your account will become Premium and all the Premium options will be unlock.