Trim the input on the channel you wish to effect using the "Gain" knob at the top of the channel. Adjust this setting so that the green "Signal" light located next to the channel's fader is illuminated. If the red "Clip" light is illuminated, reduce the gain until it only flickers intermittently.
Locate the "EFF 1" knob on the channel. Set the mark on this knob to line up with the small arrow marking on the board.
Locate the effect selection knob on the left side of the two effects unit channels. Choose one of the echo effect types. Set the fader for this channel at its zero position and make sure the "ST" button next to the fader is depressed.
Adjust the "Parameter" knob of the effects channel to taste. This knob controls the sound of the chosen effect. Use the faders of the effects channel and the chosen audio channel to adjust the balance between the original sound and the effected sound. Use the "Master" fader to adjust the overall volume of your mix.