When you open a new CubeTwister window or when you choose «New» in the «File» menu, you do not start with an empty document. Instead CubeTwister loads a document called the «Template», which contains some predefined notations, cubes and script items.
/Users/<your name>/Library/Preferences/CubeTwister
and
enter the filename template.xml
into the file chooser.
C:\Windows\Library\Preferences\CubeTwister
template.xml
into the file chooser.