Allow your distilled water to adjust to room temperature. Cold water may harm the orchid by sending the roots into shock.
Pour the distilled water over the orchid's stems and allow the water to run down and saturate the soil and the roots. Saturate the soil to ensure the orchid is able to flush away minerals and salts that have settled around the roots.
Water your orchid often to keep the soil moist. Do not water your orchid if the soil is still moist, if the top layer of soil feels dry to touch, it is OK to water.