preparing fruit for dehydration is no different than preparing fruit for consumption.
you'll want to wash all fruit thoroughly,particularly if the fruit you are going to use will be eaten with its skin,
to remove any dirt and lingering pesticides.
if necessary,pit and slice the fruit into equal-sized pieces. for larger berries or cherries,for example,you'll to cut them in half.
Apples and pears should be cored and then sliced into 1/2 inch thick slices.
The key here is that all of pieces are of similar size that dry at an equal rate.