Here is an overview of what seventh chords are, how they are named and created. This is of particular use for those looking at extending their harmonic palette in relation to the Task 3c composition. You are expected at A2 level to be using harmony that is more advanced than basic triads, power chords and purely diatonic sequences..
Once you have tried playing through some of these options, the next thing to consider is chord voicing: the order the notes are played in. This makes a huge difference to the way the chord “feels” when played in a real setting. The next post will cover some ideas for chord voicing for seventh chords on guitar and keyboard.