The current official (i.e., CRAN) release can be installed within R with:
The same command can also be used to 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 to choose a CRAN mirror, just select the first option.
Alternatively, you can download the source file or a Windows or Mac OS 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 more information on how to obtain further documentation and help when using the package.
The package is continuously being updated and extended with new features. These updates are first part of the development ('devel') version of the package, which is hosted on GitHub. If you would like to try out the devel version, it can be installed with:
Whenever a sufficient number of updates have accumulated in the devel version, it is submitted to CRAN and becomes the new official release (with a new version number).