In order to open .fxb/.fxp preset files in the plugin browser, the files must be copied to the following folder:

Windows
C:\Program Fies\VSTplugins\Waldorf\PPG Wave 3.V Sounds

Mac
Macintosh HD\Library\Audio\Presets\Waldorf\PPG Wave 3.V
Also, you can use the Add Scan Folder option to add another folderfor saving and loading .fxb/.fxp.files. For this, you need to right-click Local Library in the plugin browser.