2 things.
First, you need to set the objects to shade smooth or shade auto smooth. On the cup I’d recommend auto smooth and set the angle on the modifier to something like 15 degrees. On the gem looking spheres I’d use auto smooth set to 5. The single sphere just shade smooth.
Second, you need to set the transmission weight. I’d start with 1 for full effect. Also set the Alpha back to 1, but you don’t have to.
