The overview strip is a graphic representation of the selected audio file (the highlighted playlist item). The position within the soundfile is indicated by the yellow cursor. To change the cursor position place the mouse pointer anywhere on the overview strip and depress the left mouse button – this will allow you to sample different fragments of an audio file when tuning processing tools. The black strip around the cursor marks the local preview area. To change the size of this area adjust the local preview time using the Options dialog available from the View menu.