The mac process is similar to the Linux process, which I am familiar with.
To burn the image, you have to use the dd command (which in Linux requires superuser privileges, so you may need that too). On Linux you use "sudo" to elevate the command to superuser level, you'll have to figure out how to do that on mac. The command is fairly simple, you specify the input (with the in parameter) which is your img file (make sure you unzip it, if it came as a zip file), and the output, which is the drive representing your SD card (something like /dev/sdg or /dev/sdf or something similar). The drive has to be unmounted.
To determine the drive (/dev/sdX), on Linux you use the mount command; you can try to see if the same command works on mac.