The MaterialsAndServices catalog will store information about services that the Jack of All Trades company provides, and resources that might be consumed while providing services.
This catalog will not be complex. Its only distinctive feature is its hierarchical structure. To make the catalog user-friendly, you will combine services into a group and resources into another group.
Additionally, since Jack of All Trades provides a wide range of services, you will break them down into several groups. The same is true for resources.