You can install the package (or upgrade to the latest official release version) directly within R by typing:
(assuming an internet connection and appropriate access rights on the computer). R will then download the package from CRAN (the Comprehensive R Archive Network) and automatically install it (or upgrade to the newest version if the package is already installed).
You may receive one of several prompts during this process. If you are prompted whether you would like to use a personal library, answer 'Yes'. If you are prompted whether you would like to create a personal library, answer 'Yes'. If you are prompted for choosing a CRAN mirror, just select the top option.
Alternatively, you can download the source files or a Windows or MacOS X binary from CRAN and install the package manually. See the R Installation and Administration manual for more details on how to install packages this way.
Once the package is installed, you can load it with:
For an overview and introduction to the package, just type:
On this website, you can also find some more information on how to obtain further documentation and help when using the package.