Easiest is to use a simple extension by the SketchUp team:
http://extensions.sketchup.com/en/content/create-layout-file
- Note: That this extension has yet to be compiled with the new Ruby 2.2 libraries, so it cannot run under v2017 yet. (You can back save the model to v2016, run the export to generate a 2016 layout file, then open it with LayOut 2017.)
Forum thread for talk, bugs & feature requests: