To select a note, press escape to exit note input mode and then click once on the note.
To select a line, press escape and then double-click.
To select the staff for the whole piece, press escape and then triple-click
Use the left or right arrow keys to move to the previous or next note and control or command with the left or right arrow keys to move to the previous or next measure.
Press N to begin note entry or press N again or escape to leave note entry. The keyboard letters A through G correspond to note names. If you want to create a chord, you can add a pitch by interval using the number row 1-9 with 1 being unison and 8 being an octave. Holding down shift while pressing numbers on the number row will give you intervals below the selected note.
Control or command up or down moves the pitch up or down an octave. The up and down arrows by themselves move the pitch diatonically up or down. To change the pitch a half-step, press shift page up or page down.
Delete a selected note by pressing the Delete key.
The numpad controls many rhythm and accidental choices. Duration moves from smallest (32nd note) on 1, and largest (whole note) on 6, with 4 being a quarter note. To toggle between a note and a rest press 0 and the decimal point creates an augmentation dot. 7 will enter a natural sign with the note, 8 a sharp, and 9 a flat sign.
Additional helpful shortcuts include using the right arrow key to input a rest use the numpad to choose the duration. You can change time signatures by pressing T and enter triplets by first selecting the duration and then hitting control 3.