This is where you give your Pages a name. Think of this as a Domain name.
In the "Search Available Names" section where the word "Example" is, type in your preferred name. Some people use their first initial last name, others use their business name etc.
After you type your name in (mydoterra as an example), the system will check to see if it is available or not. If it is, a message will say that the name is available!