Vibrato lets you add natural vibrato to your playing. Vibrato is the side to side movement of your hand. It uses acceleration so it depends on how fast you move how much Vibrato you add.
You can change the sensitivity of the Vibrato by dragging the line up or down, making it longer or shorter. A longer line is more sensitive and a shorter one less so.
To map vibrato to your DAW you need to tie a MIDI message to each function. Press the MIDI icon to select Pitch Bend, CC or Note.
When mapping, Solo the function you want to map in order for Softwave to only send the signal for that particular function to your DAW. When a parameter you want to map has been selected in your DAW, move Wave in order for the MIDI message to register.
If you select Pitch Bend the function will map to a Pitch Bend parameter in your DAW.