You will need to get tested so you are eligible for coverage on your extended medical (if you have it!).
I got my latest one through Snore No More -- they were great to deal with and got all the paperwork done to get mine updated and refunded.
If you're lucky you can use the nasal pillows (most comfortable) and if not, you will have other use a partial or full mask (not so comfortable).
They take a while to get used to, can cause CNS apnea (most sleep apnea is caused by obstructions like a soft palate, extra flesh in your neck or a deviated septum) but you can also develop a condition where it's your own brain that shuts off your breathing and that's hard to treat.