This is a demo tutorial. While there is no step-by-step commentary available (yet), the live demo below is fully functional. Feel free to open it for full source code.
This demo shows how we can use Legend's hit event to toggle other series off when one series is toggled on, making sure that there's only one series displayed at any given time.
See the Pen amCharts 4: Allow just single series to be displayed at a time by amCharts team (@amcharts) on CodePen.24419