Jaksta products can automatically import supported media files into the desktop version of iTunes.  They will not import automatically to the Windows Store iTunes as that application is sandboxed.  If you are using the Windows Store iTunes you will need to import manually.
To download the Desktop version of iTunes:
1.  Goto https://www.apple.com/itunes/
2.  Scroll to the bottom of window past the prompts to install the Windows Store iTunes
3.  Click Windows next to "Looking for another version"
3.  Click the download button
4.  The desktop version of iTunes will be download to your computer and you can install it as you would any other application.