Can you display the same design on the same product but in different design colors?

I’m just starting with Spreadshirt’s new interface, and it is driving me crazy.

I have a design and I want to put it on a plain men’s t-shirt. I first set up a white design on a black shirt. That was easy enough. Done.

Now I want to add a second plain men’s t-shirt to my store. Same design, but now I want a light blue design on a dark blue shirt.

How do I add this second product to my store? If I try to use the “edit product selection” option, I can only select or deselect the men’s t-shirt. There is no option to add a second plain men’s t-shirt.

I must be missing something here. Could someone please talk with through the steps?

You have to re-upload the same design to do this!