The registration page in User Registration solution pack was created using DataAssist to insert to information in the database.
before Proceeding, it would be a good idea to make a back up of the registration page.
First, you will need to modify the Users table in the database to add columns for the new form fields you have added. Also, you will need DataAssist installed to be able to modify the Insert Record behavior to store the information form the new form fields you have added.
In the Server behaviors list, double click the Insert record Server behavior to begin editing it. Select each of the new database columns you added and click the lightning bolt next to value and select the corresponding form element.