Copy ForestPackPro.dlo to %maxroot%/Plugins

If Library Browser is empty:
File/Preferences/Add…/ C:\Users\USER_NAME\AppData\Local\Itoo Software\Forest Pack Pro\lib

3dsmax_menu/Customize/Configure User Path/External Path/Add…/C:\Users\USER_NAME\AppData\Local\Itoo Software\Forest Pack Pro\maps\