If you came are inserting the "Major Update for Sandbox Template" in your sandbox, you probably did not replace "YouHelpPage.html" with the name of your help page.
This page is not referenced by the Templates page, contrary to the "Templates" entry in the "List All Help Pages" table. There is a reference to this page in templates.html, but the reference is in a comment block. Apparently the code that puts entries in the "List All Help Pages" table fails to skip references in comment blocks.