The waveform display shows the audio that you have selected for replacement. When you select audio on the source track, then open Sound-Replacer, the audio waveform will automatically be displayed here.
Once the audio selection is displayed, you can load the desired replacement samples and adjust their trigger thresholds while viewing the waveform peaks. Trigger markers then appear in the waveform, indicating the points at which the samples will be triggered.
The color of each marker indicates which threshold/replacement sample will be triggered. The blue Trigger Envelope shows the waveform slope that determines the trigger points. The Zoomer lets you increase or decrease waveform magnification here to help accurately set trigger thresholds.
If you change the audio selection on the source track, click Update to update the waveform display. If Auto Update is selected, SoundReplacer automatically updates the waveform display each time you make a new selection or begin playback.