Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
The trial installed at the factory does not include Pro Plus. Product Keys are Office bundle specific, your key won't work on the factory trial.
You will have to uninstall the factory trial, boot the computer, download and then install and activate Pro Plus.
Pro Plus is not a normal retail version. It is a limited distribution bundle. Where did you get your copy of Pro Plus. There should be a download link associated with the purchase.
Here are some possible download links
https://downloadoffice.getmicrosoftkey.com/Default/Index - Enter your Product Key or sign in to your account
**Direct Download Link for Standalone Pro Plus Offline Installer (64-bit)** (702 MB) (you must get trial Product Key separately)
http://technet.microsoft.com/en-us/library/jj219422 Pro Plus
This site has direct download links to Digital River for some Office bundles and standalone programs:Office 2013 Home and Student, Office 2013 Home and Business, Office 2013 Professional Plus x86-x64 / Word / Excel / PowerPoint / OneNote / Outlook / Publisher / Access / Project Pro x86-x64 / Visio Pro x86-x64 / Office 2013 Language Pack . You may have to scroll down to find your language. (NOTE: there are 2 downloads, the installer and scrolling farther down the page, the *.IMG downloadshttp://www.heidoc.net/joomla/technology-science/microsoft/73-office-2013-direct-download-links
32-BIT Pro Plus CTR
Direct Download Link for Standalone Offline Installer (32-bit) (624 MB) Pro Plus direct installer file download (you must get trial Product Key separately)
64-BIT Pro Plus CTR****https://c2rsetup.officeapps.live.com/c2r/download.aspx?act=1&token=&platform=x64&Source=O15HUP&version=O15GA&ProductreleaseID=ProPlusRetail&language=en-US&TaxRegion=PR
http://www.technize.net/download-office-2013-final/ Office 2013 Pro Plus Direct Download Links (Final RTM Version) - unofficial site