Hi Tad, I'm not sure I understand. Where is that image from?
That screenshot shows the shape legend, which allows you to customize how your data values are mapped to specific shapes (including custom shapes). To get to that legend, you first need a viz which displays data as shapes. Change the mark type on the Marks card to Shape, and drag one of your data source fields to the Shape shelf. You should then see the Shape legend appear below it, as shown in the screenshot below.
I hope this helps,
Here's a question. What if you want to create a custom shape for "all" or in this case All Products?