The best way to understand setting of colorline and sensitivity is to log some charts with your Lowrance and replay them in the SonarViewer as I have demonstrated and adjust the settings at home when you are not distracted with fishing. The log chart function and the SonarViewer are explained in my Lowrance Tips section.
Definitions
Echoes: same as sound waves or signals
Colorline: same as grayline but color instead of black and white
Transducer: sends and receives echoes