When you create a Project, a resource set is created by default. This resource set is automatically connected to all components you create from within the Project. This means all Project components will have access to all resources in the default resource set.
You can also create additional resource sets. For example, you can create a resource set that contains resources used by a number of Message configurations in the Project. In this case, you must manually connect the resource set to the Message configurations.
The name of the resource set should follow the naming standard used in your organization, for example include the document type (invoice, order, etc.) of Message configurations using the resource set.