See the "How to Restrict Access to pages on your site" tutorial in the How To Section of the user Registration solution pack support page:
The protected_Page.php page is provided to confirm that your log in feature, and access restriction works on the User Registration Solution Pack. We will use this same code, to apply the same type of restriction to our pages.
1. Open the protected_Page.php file.
2. Highlight lines 1 through 6.
3. Press Ctrl (Cmd) + C to copy your selection.
4. Open any page you wish to apply this restriction to.
5. Place your cursor in the first line of the code.
6. Press Ctrl (Cmd) + V to paste this code.
Note: If the page you are copying this code to is not in the same location as the protected_Page.php file, you will need to update the path that references WA_SecurityAssist/Helper_PHP.php.