can't install font

I am having a major issue downloading the font "Cursif" for my mac from dafont.com. i tried double clicking on it as it usually works for fonts, but nothing happened besides opening the font book. i tried dragging it in to the computer area, because i read the FAQ of this community and realized it IS a ttf file..but its STILL doing absolutely nothing.
i am incredibly frustrated. but it did say download for both PC and mac, and i have a bit higher than Mac OS X.
help?
i really want this font.