Please follow the steps below:
Step 1:: Log in your back-end and go to "Extensions/Template Manager" .
Step 2:: Click on the template style "plazart_blank - Default" and open it.
Step 3:: Please do like the following image when the page loads:
- Please do not use the Duplicate function of Joomla to duplicate the template. Or else, when you change anything in one of them, it will be applied to the others.