Most electronic keyboards have a control which can automatically add an ending to songs you are playing. Press the ending button when you have finished playing a song. The ending feature has been used in most of the exercises on the recording.
You can now play the chords to accompany the melodies of the songs in Lesson 3, i.e. Crystal Rock and Ode to Joy. Go back to Lesson 3 and practice playing the melodies of those songs with the C and G chords. Remember to take your finger off the chord key immediately after you have played it, but keep your left hand fingers close to the keyboard, ready to play the next chord.