FCP Editing Basics
The Browser is where all of the clips in a project are organized. It contains all of the sequences, clips, and imported media associated with each project. "Bins" or folders can be created within the Browser to organize those items. Double click a sequence will open the timeline associated with that sequence. Double clicking a clip in the Browser will open that clip in the Viewer.
The Viewer is used for viewing a clip’s media and preparing clips before editing them into a sequence. Using the transport controls that you learned during Log and Capture browse the clip that is loaded in the Viewer. Fine tune in and out points by pressing "i" and "o". Click and drag the image from the Viewer to the Canvas to send it to the timeline.
"Insert" and "Overlay are the two choices that you will be using primarily. Insert places the media that is in between your designated in and out points into the timeline beginning where the yellow playhead is and it pushes anything that is in the way to the right. Overwrite does the same thing except that it overwrites any media that is in the way.
The Viewer is associated with the active clip (whichever one has been double clicked) and the Canvas is associated with the timeline and more specifically with wherever the timeline playhead is.