Markers Options are used to customize the Tools -- Quick Markers operations. The Marker Guides are shown in Figure 2 -- the two (blue) vertical lines at either end of the marker placement ruler.
Marker Guides Positions
Left Guide - Set the Position of the Left Guide (mm:ss). Time values from start of audio. (Factory default: 0 seconds)
Right Guide - Set the Position of the Right Guide (mm:ss). Time values from end of audio. (Factory default: 10 seconds)