It looks like you're new here. If you want to get involved, click one of these buttons!
On 025.8 on an Xubunut 18.04 box. The assistant says
Creating A Layout From Scratch
To start with a fresh, empty layout, choose "New" from the "File" menu.
But there is no "New" in the "File" menu!
There is "File > New Layout".
What was the point of your message?
It isn't there on my version. I have no layour loaded - do I need a layout loaded for it to allow me to create a new one?
I have found you have to change the "Application:Editing Mode" to Use editing mode by default and restart to get that in the File menu!
Yes, there are two modes: a viewer (optimized for viewing) and an editor (necessary for creating layouts).
Yes, there are two modes :-)
On Windows you'll get three start menu icons: a default (the one you configured in Application/Editing mode), a viewer and an editor mode.
On Linux (and Windows) with "klayout" you get default mode. With "klayout -e" you'll always get editing mode. With "klayout -ne" you'll get viewer mode.
In general, viewer mode is more efficient with big files and in particular with OASIS files.
The doc link is here: https://www.klayout.de/doc-qt4/manual/editor.html