FDM can integrate with Essbase and Planning to load and calculate data. When designing an FDM integration, factors like user needs, data workflow, and cube design must be considered. FDM uses adapters to connect to other products, allowing it to directly load data or trigger actions like calculations. Data can be loaded to Essbase using load rules or by calling the API, while calculations can be run via an external calc script or one dynamically generated in FDM.