Remember to save your files frequently.
To save you data, go to
the file menu and select save. This will save your project in an
editable project format. Your project will be saved under the name
that you gave the project when you opened iMovie. The file you will
finally save and be able to Fetch to the CD Burner will most likely be
QuickTime format, which is .mov.
Exporting your movie puts your movie in a format that is smaller, and thus easier to transfer. The exported movie does not have any clips that you did not decide to keep, nor is it in an editable format like projects are. Exporting is normally the final stage in movie making. Exporting does involve compression and it can take several minutes to export even a small movie.
To export your movie to a camera, go to the file menu and select export. This brings up a dialog box which asks whether you would like to export to a camera or to QuickTime. To export to a camera, make sure your camera is connected, select the camera option in the dialog box, and choose the options for the exported file.
To export your data to a QuickTime format, go to the file menu and select Export. This will bring up a dialog box which asks you to indicate whether you would like to export to camera or QuickTime. Select QuickTime and then select which format you would like to export to. The options are: