There used to be a forum post on how to do this in BT4 here:

When I access the page now it says I don't have permissions to view it. In any case, the instructions were for KDE and I'm using the Gnome flavour of BT5. Does anyone know how to make the desktop for all users look like it does for root? Currently with new users created via adduser it is a generic/basic version of gnome and not BT customized.

I've already tried copying /root/.gnome2 and /root/.config/ to /home/<user>/ and modifying ownership, but that didn't seem to do the trick.