You will need to have Google Earth installed on your computer.
Run your copy of Google Earth. 
File > Open and browse to where you have saved the .kmz file and click Open. 
After the kmz file is opened, you will see that kmz file listed in the 
Places > Temporary Places folder and, in GE's aerial viewing window, 
the path will be centered and highlighted (usually a thin white line, 
but may be a different color).