Place the scrubber (red line) at the split point between the clips where you want the new one inserted.
In the media bin, click on the clip to be inserted. Click the chevron to the right of the PLACE button and choose PLACE ON SEQUENCE AT CURSOR.
Or...
Hold down <alt> as you right-drag the clip that will follow the clip to be added. This will create a gap. Insert the clip there.
Close any gaps by placing the pointer in the gap, right-clicking, and clicking on CLOSE GAP. Gaps may be easier to spot in Storyboard mode.
If adjacent tracks are adversely affected when inserting the clip, lock them first by clicking the lock icon at the left of the track.
