How do I download R libraries?
Certain add-on shareware procedures in R, called packages, are contained in folders which contain suites of R programs. For example, to read SPSS data into R you need the code in the folder called foreign. In order to obtain these folders you go to the R home page located here and click contributed extension packages and download the appropriate folder into your existing R library folder (assuming you have already downloaded a version of R). The SPSS or other data set may be placed in the bin folder located along with the library folder in the R folder which serves as R's home data directory .
Alternatively IF you know the name of the library you wish to install from the R website you can use the install.packages command to install packages directly into a R session without visiting the R website. For example
install.packages(c("lme4","nlme"))and then choosing UK (Bristol) in the resulting window will download and install the libraries called lme4 and nlme.