The next four songs contain first and second time bars. This means that the first time through, you play the notes under the Z, then go back to the beginning of the song and play it again. The second time through, you do not play the notes under the first time bars, but instead play the notes under the X.
In the song Jingle Bells, play from the beginning to the end of bar 8. Then repeat from the beginning and play to the end of bar 6. Then miss out bars 7 and 8, and play bars 9 and 10 to finish the song.
The black box hanging from the fourth line of the staff in bar 10 is called a whole note rest, sometimes called a semibreve rest. In ^ time it has a value of three counts (the whole bar).