To install Dual you can do so in one of two ways:
1. The Simple, No Brainer, Piece of Cake Way:
Upload the provided dual.zip file via the WordPress Admin Panel. To do so, go to “Appearance” > “Themes” in the menu, then select the “Install Themes” tab at the top of the page. Once you are at this page, select “Upload,” then “Choose File” to locate the .zip folder on your computer. After doing so, select “Install Now.”
2. The Roll Up Your Sleeves and Use a Little Elbow Grease Method:
Uncompress the provided dual.zip file and upload the template contents to the /wp-content/ themes/ directory of your WordPress installation via your chosen FTP client.
Neither method has an advantage over the other, it is simply a matter of preference.
Follow the same instructions above to install the Dual-Pro Premium theme, but download the dual-pro.zip file instead of the previous zip file.