Unzip the alpus-pro.zip file. You will be able to get it from the package you downloaded.
Connect to your FTP server using FTP client and navigate folder where wordpress is installed.
Navigate to the wp-content > themes and upload alpus-pro folder on it.
Login in to wordpress admin panel with your admin account and navigate Appearance > Themes and activate theme.
After activate theme, please follow steps to setup your site dummy contents such as child theme, plugins, demo content, etc