You'll have to replace the code on line 450 to use confirm validation, so the code:
var Confirmemail_Spry = new Spry.Widget.ValidationTextField("Confirmemail_Spry", "none",{validateOn:["blur"]});
would become:
var Confirmemail_Spry = new Spry.Widget.ValidationConfirm("Confirmemail_Spry", "EmailAddress");
Then you would have to make sure to include the confirm validation .js and .css files in the header and upload them to your server.
The easiest way to do that might be to put the cursor on the bottom of your page and go to Insert->Spry->Spry Validation Confirm
Then save the page and it will automatically add the necessary files to the site and to the header. Then you can copy the code added to the header and use ctrl+z to undo the insert. Then paste the .js and .css code back into the header.
