You have two (free) methods of organizing your sound libraries...

_ you as an use the free downloadable "Yamaha Motif XF Editor Standalone/VST".
_ you can use the MediaBay/Sound Browser that is built into Cubase.

Together they work as a very elegant way to both archive and manage your Voices and Mixing setups.

The Yamaha Motif XF Editor, which can be used alone, will allow you to manage data file by file. But when used as a VST3 plug-in within Cubase, the MediaBay/Sound Browser allows you to manage every Voice you amass in a single huge customizable library (worth using whether or not you are Cubase user).

Your Voice files are housed on your computer (Windows or Mac) and you are free to reorganize data as your prefer. Cubase is able to manage every Motif XF file in one large librarian. You can further customize access using your own folder system, if you prefer.

The Cubase Sound Browser is specifically a Librarian that allows you to manage all your sounds (Voices and Mixing setups) that you create or amass for your synthesizers. It will allow you to click on a Voice to recall it - it is sent to your instrument's Edit Buffer. For auditioning Voices quickly and efficiently - it cannot be beat. This means you can have access to literally hundreds and hundreds of Voices, categorized and ranked (by you) for instant recall. This works for regular Voices and even with Voices that utilize your Flash Boards for custom Waveforms and Samples. It is the ultimate way to organize and access your custom Voices and Mixing setups.

We have an article introducing you to the Editor and to the Cubase Sound Browser here on Yamaha Synth:
Adding Voice Libraries as VST Presets

Article introducing the Motif XF Editor is found here:
Motif XF Editor VST

The Yamaha Motif XF Editor Standalone/VST is available from the official Yamaha download site: http://download.yamaha.com

If you have questions post back here.