From the Modelon Impact landing page, you can create a new workspace for your work, or open/import an existing workspace. A new workspace will contain only the Modelica standard library by default. To add more existing content, e.g. any of the Modelon libraries, open Workspace Configuration from the Apps menu in to top right of the browser window. From there, any libraries that are needed can be added to the workspace. Checking out content from SVN/Git is also supported. See more information in Workspace Management. When going back to the workspace in Modelon Impact, you will be prompted to reload the page to load the new content.
All Modelon libraries require that the Modelica Standard Library ("Modelica") and the Modelon Base Library ("Modelon") is loaded as these contain components that are extended to other libraires and models. The Modelica Standard library is loaded by default in Modelon Impact, but the Modelon Base Library needs to be loaded in Workspace Management when loading another Modelon library. The AirConditioning library is dependent on the ThermoFluidPro library, which needs to be loaded when working with the AirConditioning library.