When Show Advanced Tools is selected in the Advanced preferences pane, you can add notes and other symbols from the Part box in the inspector. The Part box contains a complete collection of score symbols, arranged in groups. You can control which symbols are displayed in the Part box, reorder symbol groups, and open the Part box as a separate, floating window.
The Part box includes the following types of symbols:
Notes and rests
Key and time signature symbols
Clef signs
Slurs and crescendo/decrescendo symbols
Note heads
Accents, bowing marks, fermatas, and other symbols that apply to specific notes
Phrasing marks
Trills and other ornaments, tremolo symbols
Sustain pedal markings
Bar lines, repeat signs, and Segno and Coda markings
Lyrics and text
Chord symbols
Chord grids and tablature symbols
Page and line break symbols
With the Score Editor open, click the Inspector button 
in the control bar.
If the Part box is closed, click its disclosure triangle in the inspector to open it.
Drag the Part box out by its title bar.
Click the disclosure triangle for the Part box in the inspector.