This Recommendation covers the following aspects: APIs invocations framework for testbeds federations reference model defined in ITU-T Q.4068; Workflow Scenario Illustration involving a user accessing and using a testbeds federations ecosystem based on the testbeds federations reference model APIs defined in ITU-T Q.4068 and the extensions listed in the Recommendation ITU-T Q.4077; Security framework that should be applied to the Testbeds Federations Reference Model in ITU-T Q.4068; Instantiations of the Testbeds Federations reference model, and transformation of existing IMT-2020/5G related testbeds APIs Key Performance Indicators (KPIs) specific to testbeds federations