You map the source data to the target dimension in the application. In addition, you can define simple transformation rules using expressions.
When mapping dimension for a file-based integration, if the source file has a header record or you defined column headings in the preview section, select source columns for each dimension. Data Integration automatically determines the column number and populate the column number. You can also manually enter the column number.
For direct integrations, you can pick the dimensions from the Source Application and map to the dimension in the Target Applications.
For both file-based and direct integration sources, you can also apply source and target expressions that operate on source and target dimensions.
Watch this tutorial for information on mapping dimensions and members: Mapping Dimensions and Members for File-Based Data Integrations in Enterprise Planning Cloud