Hi Frank,
generally the Soprano would be the top note and the Alto the next one down, but I'm sure you know that.
I would actually like a bit more context from the score. E.G. is it an SATB score, or Piano/Vocal or what?
The reason I ask is that if the staff immediately below is singing the same words at the same time (I.E. a Tenor/Bass part), and is in Bass clef, then the A that is in the middle of the chord in question is mirrored in the bass and could probably, if necessary, be left out.
Without context it's difficult to be sure, but they may be expecting more voices than just Soprano/Alto. Maybe Sop/Alto/Alto, or Sop/Sop/Alto... Any number of possibilities.
Also, are you aware that you can create chords on a single staff without layering?
If not, please see the "Chord Member Command" in the Help screen.
Layering is often the best choice for complex chord structures, but not always necessary. It IS very important when wanting to print separate parts for each voice while still being able to see them combined when appropriate.
See below for an example of chords on a single staff. Click Select, <Ctrl+C> to copy to the clipboard and then paste it into a new staff, or as a new file, in NWC:
!NoteWorthyComposerClip(2.751,Single)
|Clef|Type:Treble
|Key|Signature:C|Tonic:C
|TimeSig|Signature:4/4
|Rest|Dur:Half
|Rest|Dur:4th
|Chord|Dur:8th|Pos:-3,0|Opts:Stem=Up,Beam=First
|Chord|Dur:8th|Pos:-3^,-1^,1^|Opts:Stem=Up,Beam=End
|Bar
|Chord|Dur:16th|Pos:-3,-1,1|Opts:Stem=Up,Beam=First
|Chord|Dur:16th|Pos:-6,-3|Opts:Stem=Up,Beam
|Chord|Dur:8th|Pos:-6^,-3^|Opts:Stem=Up,Beam=End
|Chord|Dur:4th|Pos:-6,-3
|Rest|Dur:4th
|Chord|Dur:8th|Pos:-1,1|Opts:Stem=Up,Beam=First
|Chord|Dur:8th|Pos:-3,0|Opts:Stem=Up,Beam=End
!NoteWorthyComposerClip-End
Also see attached Vocal Ranges file - N.B this is notional only - different authorities have different ideas.