How to HDL load Document Record attachment which is generated by BIP report?

Summary:

In our new hire onboarding process, the new hires will provide information on the documents. The filled documents need to be batch loaded to Document Records attachments. I'm stuck how to batch load, details are below. Could anyone help? Thanks!!

Content (required):

1. We created a Journey, Journey task is a Questionnaire. The new hires filled in the information, for example,

2. We create a BIP report to retrieve the new hire's name, and his/her input data stored in Questionnaire table.

3. In Document Type, we defined the BIP report.

4. On "Document Records" page, when I clicked "Add" button on user interface, it works, a PDF attachment is created based on the BIP report.