Hi, Please download the attachment. You will find database.php file from 

invoice/application/config/database.php 

and then put that database information (See install.png file). 

Before do that you must import the database to your database. 

You will find SQL file database.sql under invoice directory.

You can translate all files from invoice/application/views/

Installation Files: https://www.dropbox.com/s/9aqq382hd30d041/Invoice.zip?dl=0

Thank You
Francis