This document has the basics for opening a case, along with section 3.5.4 on sending doc to the case via FTP or SFTP
It basically says to use port 22 for SFTP or port 21 for FTP, which is standard.
It includes a link to what you really need, which is the Broadcom Case FTP Help Document
When you scroll down, there is a section
FAQs About Transferring Files Without Using the Broadcom Support Portal
and another section with JCL examples titled
How do I transfer files to or from a mainframe securely?
That last section also includes the z/OS configuration needed for SSL, including the certificate you need from us to run it.
It also includes JCL examples for uploading and downloading the doc.