To obtain a copy of ELMER, you will need to install devtools and ELMER.data which contains essential data for running ELMER package

install.packages(devtools)
library(devtools);
devtools::install_github("lijingya/ELMER.data");
devtools::install_github("lijingya/ELMER");

Then you can load the package and see an introduction with

library(ELMER)
openVignette("ELMER.data")
openVignette("ELMER")

# Please select a vignette:
# 1: ELMER - ELMER: Inferring Regulatory Element Landscapes and Transcription Factor Networks Using Methylomes
# Selection: 1

Or you can have the vignette, and sourcecode for the vignette open directly in the browser

browseVignettes("ELMER.data")
browseVignettes("ELMER")