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.
If you have multiple axes and a chart cursor, each axis will get a tooltip when you hover plot area. This demo shows you you can use adapters to consolidate values from multiple axis' tooltips into one.
See the Pen Consolidating values from multiple axes into a single tooltip by amCharts team (@amcharts) on CodePen.24419