You can install theme via 2 ways: Via WordPress or via FTP.
Akeeba installation
The Akeeba allows you to replicate template joomla demo to your server. It means, after install the Akeeba, you will have a site exactly the same as the demo site.
After upload template into your server and extract it, just Akeeba installation as below:
Step 1: Extract file for each demo
Extract file tazza_fullsite.zip:
After extract, you follow these steps:
Enter infomation connect your database, click Next
Input your information and password login to administrator, click Next:
Click Next and remove instalation folder:
Install finished.
In admin page, go Extensions -> Manager -> Install
Click to tab Upload Package File, and choose file
Select file template.zip:
Click Open install template