Adding fields to the New User Registration page requires a couple of steps:

First, you must ensure that the fields are visible, and set to be used.
This is done under Setup -> Database Configuration
Once you find the field you would like to add, you must do the following:
  1. Make sure the 3rd column over "Use this field" is checked. 
  2. Next, you will want to make sure the 4th column "User can see" field is checked.
  3. Then the 5th column "User can change" must also be checked.
  4. You may select the 6th column "Required for registration" but you can also set that in the next phase, so it it not required.
Save your changes and then logout of Luminate, and log back in.
  1. Now go to Setup -> Standard Page Center
  2. Select Constituent Profile (User Registration) and click customize
  3. Go to Step B. and click Select Attributes to Display, and select the fields you want to show
  4. (Optional) Step C. Select Required attributes, and select which ones are to be required
  5. Save all you changes and the new user registration page will have the new fields.