The data sets for the ISLR book (second edition) are listed briefly on
pp. 13--14.  To get them, you must install the ISLR2 package from 
https://cran.r-project.org/.  In Rstudio this is easiest to do by
going to the Tools menu, selecting the first option (Install
packages...) and following your nose.  You can also do this at the R
command prompt, with a command like install.packages("ISLR2").