What is the syntax for making a page auto-redirect to a different HTML file in a separate folder? All of my searching returns how to redirect from one website to another.
Its a late answer, but as I can see most of the people mentioned about "refresh" method to redirect a webpage. As per W3C, we should not use "refresh" to redirect. Because it could break the "back" button. Imagine that the user presses the "back" button, the refresh would work again, and the user would bounce forward. The user will most likely get very annoyed, and close the window, which is probably not what you, as the author of this page, want.
Use HTTP redirects instead. One can refer the complete documentation here: W3C document