How to Install Templates in Joomla 3
Adding new tempaltes to Joomla 3.x is an easy and straight-forward process. If you have experience with previous Joomla versions, you will find it very similar to what you're used to. First, you need to go to Extensions -> Extension Manager.
On the next page, click on the Choose File button and select the template archive from your local computer. Once you do that, simply click on Upload & Install button.
Once you do that, you should wait for the template to install. Once this process is over, you will see a green message indicating that the template has been installed successfully. Under it, you will see a brief information about the template you've just installed.
Finally, you need to make the template default for your website. To do this, go to Extensions -> Template Manager. On this page locate the newly installed template and click on the star button next to it.
That's it! You can now browse your website and enjoy its new looks.