Classical guitar music is often notated in two separate parts. The purpose of this is to clearly see each "voice" or "part" of the music. This mainly is used to show the separation of the bass part (played with the right hand thumb) and the treble part (played with the right hand fingers). Study the following example which uses a bass note on the first beat of the 1st and 3rd bars.
An alternative method to notate this is to separate the bass part from the treble part. The bass note D on the first beat of the 1st and 3rd bars can be notated as a whole note and tied to another D note in the following bar. This is shown in the following example.
The treble part can also be notated by placing a rest on the first beat of the 1st and 3rd bars.
Once you can see both parts separately it is then possible to visualize both parts on the same staff.
You may have noticed in the previous exercise, all the melody notes have their stems up. When guitar music is notated in two parts, the bass notes (right hand thumb) are written with the stems down and the treble notes (right hand fingers) are written with the stems up. This is highlighted in the following exercise.