We intend to develop a unified mathematical framework of quantum networks based on higher-order quantum maps and process matrix formalism. This will allow us to understand the properties of quantum networks by defining their capacities based on the particular information processing tasks. We will develop discrimination protocols for quantum networks using higher-order maps and testers to decide the suitable networks for the specific tasks. We will exploit the spatial as well as the temporal correlations offered by quantum networks to have better fidelity of success. An important feature of this formalism is that it generalizes the notion of discrimination of quantum operations.