The rsync command is already installed on OS X/macOS. When using it to copy files on the Mac, always use (at least) the -aE flag to ensure that you copy extended attributes.
Google search these unquoted terms: Apple rsync how to
Never directly download any rsync related visual tools from the macupdate downloads aggregation site. Always get these tools directly from the developer's website. You will usually avoid any malware mischief from the macupdate site by not downloading from them.
In the Terminal:
man -t rsync | pstopdf -i -o ~/Desktop/rsync.pdf
or
open x-man-page://rsync