First make sure you follow the full installation manual: https://spjsblog.com/dffs/dffs-installation-manual/. This includes the installer page.
Once that is done, yes, you create a custom list. Create the columns you want in that list. Then you go to that installer page and find the list and install dffs on the list.
Then you access the configuration by clicking the link at the bottom of the form. Usually you start with NewForm (clicking the New button) and start configuring that.
There’s a ton of options and they are explained in the user manual. https://spjsblog.com/dffs/dffs-user-manual/ It can be as simple or complex as you need. Have fun!