This course is not about database design or product preferences. It is about RPG. The primary use of RPG, though, is to manipulate database files on the AS/400.
From the user's viewpoint, IBM's database is much like any other database. You have files that contain records that contain fields.
For this part of the course, we are using the QCUSTCDT database that should have been included on your AS/400. (Your results may vary, but I found mine in QIWS/QCUSTCDT)