How to map my source data to my Target Data Extension?

assuming you prepared a data extension in advance to save your selection, you can follow the following steps on the output step first, select if you want to create a new de, or select an existing one after choosing your data extension, you will see that all the fields from this data extension appear on the right side of the screen, and your source data extensions/data views will appear on the left hand side under the available fields section you can now map the fields (choose how to populate each target field with any of the source fields) manually by drag and dropping the correct fields to the right delete mappings at any time you can delete existing mappings mappings can be deleted one by one by clicking the delete icon next to the name of a field in the mapping table alternatively, all current mappings can be deleted by clicking the trash bin button inside the tools option in the upper right corner this can be useful when you want to switch one of the source data extensions note that when you switch to another target data extension, all existing mappings will be lost