# Dynamic file names are tricky ## Sources ### Amazon S3 bucket 1) In a Taskflow, create an assignment task and add a function.  2) Add a template file to your S3 bucket that includes all headers and full example of the dynamic file name (for example, MyFile_20230512.csv). This file will need to remain in your bucket for the life of the integration/mapping.  3) Add into the **Mapping Task** source Advanced settings the input parameter from the Assignment task.  ## Targets