Each card is one item shape (items that share the same 3D model). Click one, then drop, paste (Ctrl+V) or pick your reference render. It's laid over the 3D model so you can drag the model until it lines up, and use Size / Tilt to match. Save and every item with that shape re-renders at that angle. The blue Whole category card sets the default for everything in the category that doesn't have its own angle.