Select the Open documents which were open last time you quit to keep a consistent workspace between OmniOutliner sessions.

The Create new document checkbox gives you a new, untitled document to work on each time you start OmniOutliner.

The Edit New Document Template button opens the default new document template outline; any changes you save to this outline will appear in each new outline you create.

OmniOutliner can automatically save a backup of your files as you work on them; if something unfortunate happens you can then recover some of your work.

OmniOutliner can turn anything you type that looks like an URL (web site addresses, FTP addresses, and so on) into a location attachment, which can be clicked to open the address in the appropriate application.