Log into your 123-reg e-commerce package.
Click Content/Categories and select New from the drop down bar.
Choose Sitemap from the list shown, give the sitemap a name and then select yes to make the sitemap visible on your site.
Click Insert to add your sitemap.
To delete your sitemap:
Simply click Content/Categories and select Datasheet view from the drop down bar.
Now click on the sitemap you wish to delete.
You can now delete your sitemap by clicking on the Delete button.