Basic concepts

First your files are safe. Never going to delete files. Even for move/rename operations. In any case you'd have the same amount of files before and after processing.

When you click [Start] it just analyzes the filenames/structure. Click [Cancel] to preview if you like to disregard any changes/suggestions.

Of course you can edit the entries on Preview dialog (The ones on out & out dir columns). Double-click on a cell in order to edit it.

After you are satisfied just click [Confirm]