Ok
Unzip the Kindlegen program.
Change the folder name to "KindleGen" instead of whatever it was called.
and put it here:
Make sure you .epub is on the desktop
Open the terminal and type the following:
cd ..
[make sure you put the space between the cd and the ..]
pwd [this shows you what directory you are in.]
now for the important bit.
cd desktop [changes directory to the desktop]
~/KindleGen/kindlegen Wannabee.epub