If you are following a Kenwood World app recipe, the recipe will tell you which disc to use. If you are following your own recipe, here are some tips on which discs to use (for ease of reference, the discs have identifying numbers marked on them): Disc No. 1 - Extra fine grating disc for Parmesan cheese. Disc No. 2 - Fine grating disc for cheese and firm fruit or vegetables. Disc No. 3 - Coarse grating disc for cheese and firm fruit or vegetables. Disc No. 4 - Thin slicing disc for cheese and firm fruit or vegetables. Disc No. 5 - Thick slicing disc for cheese and firm fruit or vegetables. Please note: Dependent on your model variant, you may not have all discs available. If you need any more help, please contact Customer Support for assistance.