In some cases, it is not readily apparent how to write a particular note with 
a sharp or a flat in the Score Editor.  As an example, say we want to write a 
'B flat' in the key of B minor:

How to make a 'B' note display (and play) as a 'B flat':
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1. Choose the key you want from "Bar" in the "Display" menu. Where it says 
   "Key Signature", select 2 sharps. 

2. Enter the desired note (in this case 'B') with the pencil tool.  

   NOTE: Since 'B flat' is not available, we will choose 'B' and add the flat
         in the next step. 

   

3. Select the arrow tool.  Double click on the note head, and go to
   "Enharmonic Spelling" > "Show Accidental" from the Edit menu that pops up.

   

   A natural symbol will now appear next to the note.

   

4. Select the N/S tool.  

   

   Left-click and hold on to the note head, and use the 'up' and 'down' arrow
   keys on your keyboard to move the note up or down in half step increments.
   In this case (in the key of B minor), holding down the mouse button and 
   clicking on the down arrow will automatically give you an 'A sharp'.

  

5. Since we want to write a 'B flat' and 'A sharp' is enharmonically the same 
   as 'B flat', all you have to do now is change the accidental.  Do so by
   selecting the arrow tool and again double-clicking on the note head.  
   Go to "Enharmonic Spelling" > "Flat".  The 'A sharp' is now displayed as 
   a 'B flat'.

  

The concept behind this "trick" is this: 

Enter the note first before worrying about the accidental.  In the example 
above, we made a 'B' note first and then we changed that note to a 'B flat'. 

Keep in mind that when you click and hold on a note head and use the up 
and down arrows, the program is adjusting the note up or down in pitch in 
half-step increments.  You simply change the note to the "correct" accidental 
afterwards.

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