This article applies to the 123-reg InstantSite package.
This article will explain how you can configure your external page on your InstantSite.
Scroll down to the Create your website section and click on the InstantSite icon.
Click on the Login button next to the relevant InstantSite package.
Click on the Edit link.
Click on the External page in the Site map section
Enter the external link that your would like to point your users to.
Click on the Save Changes button.