Welcome on the forum [:)]

The paid version proposes the 1610 models available at Free 3D models page. As you may download them separately with the free version, this make no difference if you installed them all. Just check you use the Microsoft Store version in the About dialog box. As the paid version has no desktop shortcut, users who keep the free version along with the paid version continue sometimes to use the free versoin.

If you installed more (possibly not translated) furniture libraries and want to remove or reorganize them, you'll find the folder where they are installed by clicking on any SH3F file listed in the Furniture libraries section of the Libraries in use pane. The latter pane is displayed by clicking on the Libraries... button shown at the bottom of About dialog box.
To reorganize the categories of furniture found in a SH3F file, you can use the Furniture Library Editor, but if you edit a SH3F file stored in the libraries folder explained above, you should rather quit Sweet Home 3D first.