If I remember correctly, the analog configuration is the default, and doesn't offer as many options but is very easy to setup.
In 2012 when I last used this sensor, there was no WPILib class that supported it, but if they've added one, you'll want to use it; otherwise you are welcome to use my 2012 code here:
https://github.com/TeamExcel/Project...angeFinder.cpp
https://github.com/TeamExcel/Project...gRangeFinder.h
You may have to configure the sensitivity ANALOG_RANGE_FINDER_DEFAULT_INCHES_PER_VOLT in the .h