You must provide at least one model resource definition for each type of resource to be autoinstalled. When a resource is requested that does not have an installed definition, CICS® creates a definition based on what you have specified in the model. You can have more than one model, depending on what properties you want the autoinstalled resources to have; for example, if you had 500 terminals all with the same properties and another 500 with a different set of properties, you could have two model terminal definitions, one for each of the two sets of properties.