HELP! how do I make an iMovie movie compatible to be able to upload into youtube?

I made an iMovie movie, its under the size youtube requires for the videos, I use a Mac, but when I go to upload the movie, it wont even let me click on the icon of my movie I made...HELP PLEASE!
HELP! how do I make an iMovie movie compatible to be able to upload into youtube?
Click the "share" tab on imovie, and then click "quicktime"... follow the steps and then upload that new file to YouTube!