It's very easy to install Hosting Billing.
You upload the zipped file that you downloaded from Codecanyon to your server.
Unzip the archive and you will see 3 folders in the unzipped folder
These folders are documentation, hostingbilling-new-installation and hostingbilling-update
Open hostingbilling-new-installation and select everything inside, then copy or move or drag to public_html or whichever directory you was to install in.
Create a new database (It must be empty)
Open your URL and the Installer will start.
Just follow the steps on your screen and provide the required information to complete installation.