The difference between the selected choice "Show Strategy on Exp. Date" and "Show Strategy on Tar. Date" determines the date the result calculations will be based.  In "Show Strategy on Exp. Date" result calculations are based on Expiration Date of the options involved. In "Show Strategy on Tar. Date" calculations are based on a target date specified in a "Target Date"  field.

After you have selected "Show Strategy on Exp. Date" a list of the different strategies appears to the right (see picture below).

Select for example "Straddle" and "Credit Spread".

Just above the Option Matrix is another drop down window where you can set your parameters for the best strategy search ("Find Strategy"). This parameter defines the expiration months of the options you want to use in your strategy search.

If you are interested in Short Term options (number of days between the Current Date and Expiration Date less than 75 days) select Short Terms. If you are interested in analyzing options with Expiration Dates more than 75 days from Current Date, select Long Terms, or you can select All Exp. Months to build strategies based on all available options.

After you make this last selection (in this example we selected Short Terms), you can click on "Find Strategy" button which is located next to "Get Data" button.