Sorry for the late answer!
In the editor you see the Export tab in the top bar.
There you're able to export each layer of your maps.
The GM Notes are primarily used to create your notes for your session.
If you're printing your maps you I also suggest to set up you map correctly when you're creating a new map.
When the overlay appears, once you click the new map button, you will find the Map Presets select field.
There you can preset your maps size in order to fit your printing needs