This is a video demonstration of the ‘playing by ear’ exercise on page 102 of Violinworks Book 1. You can order a copy of Violinworks here.
The carol ‘God rest ye merry gentlemen’ uses the notes of the one-octave E natural minor scale that you learnt on page 101 of Violinworks Book 1. See if you can work out how to play the melody on your violin without using any music – start on 1st finger E on the D string. Start by singing (or whistling) the first few notes, work out how to play them on your violin, then gradually add more notes – always sing the notes before you play them. There is a video demonstration below.