When a piece consists of notes from a particular scale, it is said to be written in the key which has the same notes as that scale. For example, if a song contains mostly notes from the C major scale, it is said to be in the key of C major. The following song is in the key of C major. Notice how the melody notes fit with the chords. E.g. the melody goes to an A note where the A minor chord occurs, a G note where the G chord occurs, a D note at the same time as the D minor chord occurs, etc. Go through this song, writing the scale degrees under both the melody and the chords.
Here is a simple solo derived from the notes of the C major scale. As with Arkansas Traveller, notice how the modes change along with the chords. The chord progression used for this solo consists of the seven scale tone seventh chords in C Major. Learn the solo and then try using this method of soloing against some of the Jam Along progressions at the end of CD2.
This solo is derived from the C major scale in the open position. Listen to the CD to hear how different it sounds from the previous one. The main difference is the rhythm and phrasing. Once again, notice how the modes change along with the chords.