Registering interest and signing up are 2 different process right.
When you registered in the beginning with number A, they will send you the link to sign up to their plan and they will process your application with the details in this sign up form.
You can use number A or B in this sign up form to port to their service. They limit to 1 line per user.
during the sign up process it asked whether I wanted to port in my number or not. For me I did, so I keyed in my existing number.
On the order form, they assigned a random temporary number.
I didn't try to create a new number, so I don't know whether they give a list of available numbers for you to select, or they automatically assign a number.
