Update default expense account after restructure

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We are going through a restructure and need to update the default expense account for several hundred employees. I was advised by Oracle Support to use the Worker file for HCM Data Loader. I have downloaded a sample file of this with all METADATA rows but am at a lost of how to proceed with this. 

Has anyone used the Worker file to update the default expense account information for workers? If so, any information you can share would be greatly appreciated!