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 add events to Legend items that would toggle on respective series' bullets and bullet labels on hover.
See the Pen amCharts 4: Show series bullets/labels on legend hover by amCharts team (@amcharts) on CodePen.24419