Serial model forward prop not performing operations step by step?

The instructor gave the following properties to a whole serial model (He refers to it as “Layer”): “This layer allows you to perform forward propagation of the entire model instead of doing it step-by-step.”

What I extract from this is that it misses all the calculations in the hidden layers and still produces the result. Is this the meaning and if it is, how is that possible?

I was under the impression that it means that the user doesn’t have to perform the forward propagation step by step (the user doesn’t have to code the forward propagation for each individual layer). Rather, the serial model does the forward propagation for all the layers.

Yes, this should be the case