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 will show how you can place the labels below both ends of the GaugeChart's axis.
See the Pen amCharts 4: Labels at the bottom of the GaugeChart axis by amCharts team (@amcharts) on CodePen.24419