First, try wearing just the CPAP mask for short periods of time while you're awake — for example, while watching TV. Then try wearing the mask and hose with the device turned on during the day while you're awake.
Once you get used to how that feels, start using the CPAP device every time you sleep — including naps. Just wearing the CPAP device every now and then may delay getting used to it. Stick with it for several weeks or more to see if your mask and pressure are right for you.