Short: http://a-little-book-of-r-for-time-series.readthedocs.org/en...
or http://people.duke.edu/~rnau/411arim.htm
And for a longer, a book by the author of R forecast library: https://www.otexts.org/fpp/
And for a longer, a book by the author of R forecast library: https://www.otexts.org/fpp/