Go to Configuration > Manage Shipping Carrier
Click 'Add Carrier'
Click on Royal Mail Icon
Populate the form and click 'Save'.
NB. All mandatory fields are marked with a star *
Now you've added Royal Mail to your account you’ll see it appear. If it’s all filled in correctly Royal mail will soon be in touch with your account details.
Please note, It can take up to 5 days for your Royal Mail account to be created.