Tune Maker is a Document Based app
When you open Tune Maker, the first screen you see is the standard document browser view, similar to the one you see in the default Apple's Files app.
You can organize your projects the way that works best for you. You can store your files on the device or on iCloud or on any supported third-party cloud storage. You also can open Tune Maker projects directly from the standard Files app. You can easily access your tunes from different devices or even collaborate with other users if you place your project to a shared folder.