There are a couple ways to create your Light account.
Creating an Account on the Device
You can create a Light account on a Light Phone from the settings.
Settings > Account & Info > Light Account > Create/Log In
Follow the on screen instructions to create a new Light account. You will provide an email address as well as a password for your account. Once created you will can log into the Dashboard website and control your Light Phone.
Creating an Account on the Dashboard Website
You can also create a Light account on the Dashboard website by clicking "create a new account" at the bottom of the login page