This is actually a very basic kit, containing just the sensors and mounting parts. It will produce the expected voltages, which you need to interpret, to read rainfall, wind direction, and wind speed. These are also the sensors which are the most specialised, as it is easy to source other sensors for temperature, air pressure, solar radiation, and even air quality (they do have some other sensors too for air pressure etc, but these need to be mounted in enclosures).
The intention is that this would operate with something like an Arduino (or a Raspberry Pi), which would measure the voltages and run the software to display output. On SparkFun's site there is also a tutorial titled 'Arduino Weather Shield Hookup Guide V12' which gives a suggestion around components and software. It's open source, so you can decide to do it any way you want to, and experiment with it.
See Weather Meter Kit
Whether you are measuring wind speed, direction or rain, this is the Weather Meter for you.