1. Open Statistica example dataset Rats.sta spreadsheet from "File | Open Examples | Datasets"

2. Select menu "Graphs | Categorized | Box plots"

3. In the popped up "2D Categorized Box Plots" dialog, under the "Advanced" tab, click "Variables" to select Dependent, Grouping and X-category variables. You can also configure other options under this tab. For instance, select "Overlaid" as the layout if only one final graph is desired.
 

4.Click "OK" to generate the plot where data is grouped by two environment types with different colors representing strain types.