I have version 15...and how I do it is, placing the arrow line (not sure what it is called...but you can move the arrow....at the top and the red line moves with it, right) to where you want it (before or after piece you want to get rid of)..and then click your cursor on the selected audio piece (lights it up, right) and then press T on the key board. This...splits your audio recording at that point, you can do this over and over and delete which ever part you don't want.