you can add them to the page by adding a confirm form element. Go to Insert -> Form -> Spry Validation confirm
this will add a new confirm for element to the page, and a new script and CSS tag to link the confirm validation .js and .css files. find those tags in the head and copy them, then undo the addition of the new form element, you could do this by closing the page and not saving. then reopen the page and paste the script and CSS tags for the confirm validation back into the had of the page.