Have the specific knowledge base instructions.

Instructions state to in the chart, select the data series, then via Format
menu, Axis tab, click the secondary axis.

I can't seem to select the individual data series. It tends to select all
the data series and the Axis tab grays out the secondary axis toggle.

I have a simple chart requirement

total # projects
totals $ value of projects

need left axis to scale to # projects
need right axis to scale to $ value of projects.

these data are divergent and doesn't display well in a single y-axis chart.