When you hit ⌘n (File → New) this creates a draft. Drafts are regular files that aren't yet saved. To save them hit ⌘s (File → Save) and choose the folder you want to put the file in (type "root" if you want to put them in the root of your workspace).
To understand drafts better it would be useful to know that:
- Drafts are regular files saved inside
path/to/your/workspace/.draftsfolder. Nota file manager doesn't show that folder.
- The tab bar shows drafts in italic.
- When saving a draft its filename is based on the heading(h1). If there is no heading in the file the name will default to "Untitled".