ProjectTemplate is on CRAN and can be installed using a simple call to install.packages():

install.packages('ProjectTemplate')

For inexperienced users, running the bleeding edge version of ProjectTemplate is probably a mistake. It is generally less stable than the versions that have been released on CRAN and is usually a little out of sync with the documentation. That said, if you’d like to use the most recent version of ProjectTemplate, you can also install the devtools package from CRAN and then type

devtools::install_github('johnmyleswhite/ProjectTemplate')

to install ProjectTemplate from source.