The top section covers Quick Note. For more information, see Quick Note.
The next section relates to tabs. The checkbox labeled "Select new tabs as they are created" will select any new tab that you create immediately. Otherwise the tab is created and added to the window but the current tab stays connected. "Create new entry for new tabs" will cause a new entry to be created when creating a new tab. Otherwise the currently selected entry is selected in the new tab. For more information, see Tabs.
The last section controls how location tracking for entries. By checking the "Save current location" checkbox, MacJournal will save your current location with new entries that are created. The first time this happens, your computer will ask you for permission for MacJournal to know you location.