While viewing the dvd, view until you get to the beginning of the section you want to save as a clip. Then press Command – (hyphen).

A little sheet drops down. Single-click the upper “Set” button, as circled below.

Now go to the dvd controller and click the triangle button (“Play”) to continue playing the dvd (or hit the Spacebar to play). When you get to the end of the clip that you want to mark, click the lower “Set” button.

If you click “Add and Play,” the clip is added to your collection of clips and the dvd Player replays just that clip.

If you click “Add,” the clip is added to your collection and the video continues to play as usual.