In this context, by "scatter plot" we mean a plot with symbols at each data point, and no line segments connecting the data points.
Right-click on a curve and select Symbol style, then select the desired symbol. Right-click again and select Line style>None. Note that you will want to select the symbol style before setting the line style to None, else the curve will not be visible.
Alternatively, change the line type for each curve to None and pick the desired symbol type using the Symbol/Line Styles command on the Options menu. The Symbol/Line Styles dialog includes many additional settings, including line weight, symbol size, symbol frequency, etc.
Click on the toolbar.
For all curves, choose "0 - none" for the line type, and select the symbol type you want to use for each curve. Alternatively, if this is an operation you will be performing frequently, you can automatically turn off all lines and set symbol types with a macro. The following macro turns off line segments for all curves and sets symbol types for 6 curves to the first six symbol types.