A subscription of SAP Build Work Zone is an application that allows users to access the solution and its features, such as creating and joining workspaces, accessing integrated tools and applications, and personalizing their sites. A service instance of SAP Build Work Zone is a space in SAP BTP where the solution runs and where content packages and UI integration cards can be deployed using APIs. Both the subscription and the service instance require the activation of SAP Cloud Identity Services (IPS) as a prerequisite, but only the subscription requires a post-booster activation of IPS to enable user authentication and authorization. The post-booster activation of IPS is a step that must be performed after creating a subscription of SAP Build Work Zone in the SAP BTP cockpit. It involves configuring the IPS settings, such as the identity provider, the trust configuration, and the role collection mapping. The service instance does not require this step, as it inherits the IPS settings from the subscription. References:

Create a Subscription for SAP Build Work Zone

Create a Space and a Service Instance

Deploy Content Packages Using APIs

Deploy UI Integration Cards Using APIs