Appel chips is one of my favorite snack and it is a important ingredient in muesli.
This is how I do:
Slice the apples thinly and dope them is slightly salted water. place them in a thin layer in a baking sheet and dray them in the oven at 50-70°C, move around the once or twice. Dray them on till they are completely dray it take sevaearl hours.