How to set the plot type (e.g. to waterfall) and determine what measurement is to be plotted?

All this can be done from the Plot Toolbar and the Measurement Selection Toolbar: The type of plot is determined from the list box list in the plot toolbar (View->Plot Toolbar).

The active measurement is set from the list box in the measurement selection toolbar (View->Measurement Selection Toolbar) shown below.

Alternatively you can set this from Measurement->Information....