Application Setup is the process of issuing an Application Instance Certificate and a TrustList to one or more Applications running on a Device that will allow the Applications to communicate with other OPC UA Applications running on the network. These mechanisms are provided by the CertificateManager Information Model and are described in OPC 10000-12.
During the Onboarding step, the DCA is issued a Certificate that allows it to request or accept Certificates on behalf of any Application running on the Device. If the DCA is a Client it can connect to CertificateManager and request the additional Certificates and TrustLists without the need for additional approvals. If the DCA is a Server the CertificateManager can locate Applications within the DCA AddressSpace and provide Certificates and TrustLists to them.
Some Applications on a Device could have access rights that prevent the Integrator or OwnerOperator from changing the setup for the Application. This could occur if Applications are used for maintenance or protect intellectual property.