Layer sliced garlic on parchment lined baking sheet. Heat oven as low as yours will allow (do not exceed 140°F), low and slow is the key to avoiding cooking or baking the garlic. You can leave the oven door slightly open (insert a wooden spoon to hold door open a crack) with the fan on, or use convection setting to circulate the air. Dehydrate for 2-4 hours until garlic is crisp and dry and snaps easily.