Editing Staves and Formatting Parts
In Composer, the largest unit of musical data is the song. (The term "song" is admittedly inappropriate for many types of music compositions, but it is a convenient term to use.) A song is all of the music-- the performance and the notation-- that you can save and later retrieve from a Notation .not file.
TIP: Actually, the largest unit of musical data in Composer is a playlist. You might find it handy to break up a musical composition into multiple Notation .not files, perhaps one for each major section of a composition or arrangement.
The next largest unit of musical data is a "staff". A staff is the line of music throughout the song performed by one instrumentalist or vocalists, or group of musicians sharing the same notes. Some instruments have multiple staves, such as a pair of piano right-hand and left-hand staves. In Composer, a staff also holds underlying MIDI performance details. If you are familiar with MIDI sequencing software, a staff is similar to a MIDI track, except that a staff also includes notation details.
In Composer, the concept of a "part" is similar to what you would think of as an individual part that lies on a music stand as an instrumentalist or vocalist reads it. A part shows one or more staves. The part for an oboe or saxophone has only one staff. The part for a piano or keyboard instrument typically has two staves for the right and left hands.
If the song has multiple instruments or vocal parts, then the score that shows all of the instruments and vocal parts together is called the "conductor's score". In Composer, the conductor's score is treated just like another instrument part; it just happens to show all of the staves for all of the instruments.
NOTE: Instrument and vocal parts are integrated with the conductor's score. For example, if you change a note in a part, it is automatically reflected in the conductor's score; or if you change a note in a staff in the conductor's score, that change is automatically reflected in the instrument or vocal part.
In Composer, you can format a part or layout pages of a part for printing using a wide variety of options, whether the part is for a single instrument or voice, or whether it is the overall conductor's part. The main idea here is that a "part" is a primary unit in Composer that you can format independently of other parts.
The above introductions to the terms "staff" and "part" are far from adequate to help you understand their central roles in Composer. It is highly recommended that you read the topic Understanding Staves, Staves and Parts before exploring these major areas of Composer: