And so friends. I completely figured out how to set up a signal for the Trading System. For myself, I chose the Elliott Oscillator indicator. Open the indicator properties and activate the alert. Then we go to the settings of Mt4 and set our sound. Be sure to select "Select Other". The Sounds folder opens, select the desired file. We save and voila, everything works. I recorded the sound “Changes in the graph” for myself and put it in the Sounds folder.