without using the data assist wizard, you will need to do it manually. we don't have a tutorial for this, it would be simpler to use the wizard to create the pages, using the wizard you can configure everything you asked about within the wizard.
The tutorial may not mention anything about file upload, and text areas, but if you become familiar with using the wizard, you will see, as I said in my reply, that they can be easily added:
"When running the Data Assist wizard to create the product admin pages, in the Field settings section of the manage pages tab, you select for fields to be text areas, lists and file fields. For lists, you can specify them to use another table like categories to populate."