After expanding the zip file,
drag each of these folders into your themes folder.
ck_rollover_red
ck_rollover_grey
ck_rollover_brown
ck_rollover_green
ck_rollover_blue
ck_rollover_colorful
ck_rollover_orange
If you don't know how to install a theme,
read the documentation at
http://docs.moodle.org/en/Themes#Installing_a_theme.