Hi Sue,
Thanks for reaching out!
The screenshot Alyssa shared is the editing area of the Sorting Activity Block.
What you're planning to do seems a better fit for a Storyline interaction, and inserted as a Storyline Block into Rise 360.
The sorting activity in Rise 360 is for specific categories, meaning right and wrong answers depending on which category the card is placed in, so it can't have a common category pile.
You may want to try Drag and Drop interactions mixed with Hot Spot interactions in Storyline 360 for this.
Hope that helps!