We cannot change the number of layers if an input layer is provided

When the Pixel job receives two inputs (the original image and a layer), the program does not show any option to add or delete layers, and automatically it puts the layers that it needs according to the input layers. We should have the option to modify the number of layers.

In the tutorial of Pixel, I can see two buttons to add and delete layers, but in the current version, they are not in the interface. So, we do not have option to modify the layers.