How to Install new Opencart Theme

After Downloading a theme free/premium, Extract your theme

After extracting you will get some some file. There will be read me and some help file also. Try to find
\yourt theme name\OpenCart 1.5.2.1\FILES TO UPLOAD\

Copy this folder and paste into your hosting
To find out which version of OpenCart your store is running on, log in to your admin panel and this should be displayed at the bottom of the page.

Inside FILES TO UPLOAD you will find three folders: admin, catalog and image. Upload those folders to the root directory you have installed OpenCart in.

Don't worry, it won't replace any core files :)

Then you need to go to your site admin panel
http://WWW.YOURWEBSITE.COM/STORE/admin/

Then go to Home-->System-->  Setting---> Insert --> Store--> Template


Choose template and click on save