Duplicating a file
To duplicate a valence file within the Gallery view, simply long press on the tile that represents that file to show the context menu.
Gallery View (Context Menu)
After the context menu is visible, select the Duplicate option and Valence 3D will duplicate the file and add it to your gallery. The new duplicated file's name will be the original file's name postfixed by "Copy".
Duplicating multiple files
To duplicate multiple files, simply tap the Select capsule shaped button located on the top right of the Gallery view. Now tap on the files you wish to duplicate. After you tap them they will be selected (represented by an orange checkmark located on the top right of the tile, see below).
Gallery View (Selection Mode)
Then tap on the Duplicate capsule shaped button located on the top right of the Gallery view. Valence 3D will then duplicate these files and they will show up in your gallery.
After you are done duplicating, tap on the Cancel capsule shaped button located on the top right of the Gallery view to exit selection mode.