Select a song then either click the Edit (pencil) button on the top right corner and click Edit Song, or use the key command, Cmd-E.

Edit panel

 showing editor buttons  
  1. Delete/Add space in the chart (more info here)
  2. Change the size of the chord: N: normal, S: small (toggles between insert/delete/insert...)
  3. Chord quality button (enter the Chord letter then select the chord quality from drop-down menu like ^7, 7, 7b9) or use the keyboard to type in (see below)
  4. Alternative chord: click on the button to add small chords above the existing chord (Note: the player ignores them). (Click Regular chord to return to normal chord input.)
  5. Invisible root: repeats the previous chord over the specified bass note (inversion)
  6. Down arrows to add vertical spaces: They toggle between insert/delete/insert...) Often used to separate a Coda section or if inversions were used in the system (line) above
  7. Repeat endings: 1st ending, 2nd ending, 3rd ending, open repeat (toggles between insert/delete/insert....
  8. Set the Time signature at the cursor
  9. Type in any text or for repeat texts use the drop-down menu (D.C. al Coda, D.S. al Coda, 3x, 4x etc.). Move the text vertically by clicking the arrows.
  10. Song Info: edit the title, composer, style indication and key of the song. Make sure you choose the correct key signature for the chords key you are inputting, then click Set.

Some symbol buttons toggle between insert/delete/insert ... to either input or delete ( like END, Segno, Coda symbol, Rehearsal letters)

Create a New Song  information.

Editor key commands

(Key commands list on the right of menu entries. Hover mouse over the editor buttons for tool tips)

Screenshot showing editor key commands

Open editor for the song Cmd-E 
Save Cmd-S
Close Cmd-W

Single barline—left Cmd-B; right Cmd-Shift-B
Double barline—left Cmd-D; right Cmd-Shift-D
Repeat opening barline Cmd-R;   Closing Cmd-Shift-R
Final barline Cmd-]
Barlines toggle between input/delete/input, but the single and double are either right or left, so if a barline does not delete, click in the space on the other side of the barline and use the other barline equivalent button to delete instead

Chord input example:
|F7    |Bb7b9  Eb9  | is input:
f 7 [return][return][return][return] cmd-B  b b 7 b 9 [return][return] e b 9 [return][return] cmd-B
or to save space f 7 [return] cmd-B  b b 7 b 9 [return] e b 9 [return] cmd-B (change to Font size small)

Use ^ for maj, hyphen for minor (-), lowercase letter o for dim, option-o for half dim (depending on keyboard language settings) (ø)

Delete key, pressing repeatedly moves backwards towards the beginning of the chart, deleting one-by-one, chord quality, chords, text, barlines etc.

Font size (remains in place until the other is inserted)
Cmd-Option-N Normal size font (toggles between insert/delete/insert)
Cmd-Option-S Small size font (toggles between insert/delete/insert)

N.C. type lowercase letter  n

Double-click inside a measure to play from that measure (click on the chart to Stop play)

Single measure repeat - %
Two measure repeat - x

Cut Cmd-X 
Copy Cmd-C 
Paste Cmd-V 
Paste insert Cmd-V; measures will move forward
Paste over select a range of measures the same as for the cut/copy, Cmd-V; measures selected are deleted
Insert space select the number of spaces where you want to insert blank space, right click

showing selected measures, right-click options


Slash ( / )
Use the / key on your Mac keyboard.
(Indicates a beat or serves as a slash for the bass note in case of inversions like G/D)

Space (at the cursor, )
Cmd-\ Insert space (everything moves on by a space)
Cmd-delete key Delete space (that space is deleted, everything moves back a space)
See this

Customize your own key commands information