Apple Final Cut Pro 7 - Manual (Page 111)

Chapter 5 Basic Editing 111
Experiment with setting up split edits. 5
Click the Linked Selection button to link the video and audio tracks again. 6
Add a short cutaway shot to a sequence:
Position the playhead in Sample Clip 3 in the Timeline at the approximate position
1
shown below, and press I to set an In point.
Place a sequence In point
approximately here.
Press the Right Arrow key 15 times to move the playhead ahead 15 frames, then press O 2
to set an Out point at the approximate position shown below.
Sequence Out point