Timeline preview is a feature that allows you to preview your
timeline before cutting it.
You can check if the parameters (silence size, talk time, paddings, noise level, ...) are correct and adjust them if needed.
The noise level set earlier is represented by a
horizontal red line in the preview.
You can also see the dB level of your audio file by moving your mouse over preview.
To navigate through your timeline, you can click on
▶ buttons, this
will move your preview by 5sec in the desired direction.
You can also click
Center on indicator to move the preview to your current cursor
position in Premiere Pro.