Hi
Note also that if you select the sound clip from the audio files bin (top left) you have a choice of placements including the Start; End; the red cursor or an overlay track at the cursor position. The default placement is set under Options/Media
Existing timeline clips will be moved depending on the choice made. The overlay track shouldn't move any of the upper clips along. Direct dragging and dropping of the audio onto a lower (overlay) audio track also shouldn't disturb upper tracks.
Practice a bit with the options on a few clips to see what happens.
Nat