1.
Select Help > Sample Data Library and open Spring.jmp.
The table has a row for each day in the month of April. The column named April is the numeric day of the month, and the remaining columns are various weather statistics.
2.
Select the Overlay Plot command from the Graph menu.
3.
Select Humid1:PM and Humid4:PM and click Y.
4.
Select April and click X.
5.
The plot shown in Plot with Legend appears. Initially, this platform overlays all specified Y columns. The legend below the plot shows individual markers and colors that identify each Y column.
Plot with Legend
To help you quickly differentiate between the Ys, select Y Options > Connect Points from the Overlay Plot red triangle menu. Adjacent points are connected for each Y variable, as shown in Plot with Connected Points.
Plot with Connected Points

Help created on 9/19/2017