How to Prune daffodil 'Interim'?
Deadhead as the flowers fade, but allow the leaves to die down naturally

daffodil 'Interim' · Narcissus 'Interim'
Plant bulbs in autumn, at one-and-a-half times their own depth, slightly deeper in light soils and in grass, in well-drained soil that is moist in the growing season in spring, in full sun or light dappled shade; for more advice, see daffodil cultivation
Deadhead as the flowers fade, but allow the leaves to die down naturally