If you're trying to install NOOBs on your Raspberry Pi, and you're on a Mac and don't want to install the SD Formatter utility almost every site out there says you need to, this is all you have to do.

1) download NOOBs (https://www.raspberrypi.org/downloads/noobs/)
2) Open a command terminal (hit Command+Space then type "terminal" and hit enter)
3) type "diskutil list" and look for the /dev/disk# with the size of your SD card.  (Some folks recommend running diskutil list twice, once before and once after inserting the SD card so you can identify the difference)
4) type "sudo diskutil eraseDisk FAT32 RASPY MBRFormat /dev/disk#" replacing # with the number you identified in step 3
5) type "cd /Volumes/RASPY;unzip ~/Downloads/NOOBs_v2_0.zip;cd" (or whatever the filename is you downloaded)
6) type "diskutil eject /dev/disk#" where # is the number you identified in step 3

There's no need to download and install a separate app.  Yes it makes installs easier, but if you're comfortable on the command line you don't need it.