For the application layer, we need to create another project.
Follow these steps to start creating the application layer:
- Create another project, as follows:

This project will contain the application service as well as the necessary interfaces required for the external world.
- We add the reference of RestBuy to RestBuy.Application, as follows:

- Next, we will start to define our interfaces. For starters, let's define an IQuery<T> interface in Services/Queries (create these folders if they don't exist) folder ...