Audio Editing In FCE

[Neil Bennett]

Hi List,
I am a recent crossover from iMovie 2 to FCE and are having problems 
'getting the deal' with audio editing.
As an example, when I was using iMovie if I had imported a 20 second 
'master' clip into the timeline, I could then paste additional clips 
'over the top' of this 'master' clip having the option of either using 
the 'master clips' audio or the incoming clip audio.
It doesn't appear to be the same case in FCE. I have read sections of 
the electronic instruction manual and have come across a section 
referring to the use of split edits. Is this what I need to understand?
Some guidance from the 'old heads' would be very much appreciated.
Kind regards
Neil