Well,
the -r means to recurse the directory. This is the main option. It'll make sure you copy all the files inside the directory as well as all the sub directories etc.
the -f means force, and this probably is not necessary, but sometimes cp defaults to asking for a confirmation to copy the files (copy /home/file.txt? [Y/N]) etc etc, this just keeps it from asking any of these questions (especially since you can't answer them).
Hope that helps!
Chris King