Here is a video that illustrates the process. Written instructions are below...
Here are instructions for installing your purchased Expansion Sounds for Notion or Progression:
1. Download the purchased Expansion Sound or Sounds from your my.presonus.com account. You can find them under Products>Notion Instruments, which is under the Virtual Instruments and Effects section in the panel on the left.
2. To download the expansion sound simply double-click the image to be taken to the page for the Expansion Sound and click on the blue download button.
3. Once the sound has been downloaded, double-click to install.