hi i need my clock changing on my NEFF oven!!!!!!!!!!!!! please help me!!?

hi, my name is andy and i was just wondering if some one could tell me how change the time on my NEff electric oven it has four buttons on the top left hand side (one with a bell marked on and one with hand, but i tryed this and it didnt work, i dont know what type of oven i have but i have got this number if this is any use! BAP217, if some one could please help me with this i would be greatful thanks andy!!!!!