to add Tell A Friend As Popup on homepage (or any other page):
1. Add new blank page in your website, on page settings panel, visibility section, enable : Hide In Menu and Hide template options
if you use floating login, you may also want to disable floating login on this page : you can do this in page protection (page settings panel)
2. Add tell a friend widget (widgets --> forms --> tell friend) on this blank page, in Tell A Friend widget settings, enable option Refferer
3. go to your home page (or any other page), add button (or hyperlink), open button properties, select Link Type : internal page and navigate to page created in 1.)
select target : new window, popup or multibox