Let me assure you now that it will hurt like hell the first time.
The Brazilian takes everything off except a thin strip at the front. The Hollywood takes it all off.
It helps to take a painkiller or a stiff drink beforehand if your pain threshold is low. But the more often you do it, the pain lessens and eventually with a good waxer, you'll barely flinch. The trick is to stay as relaxed as possible and take a deep breaths.
Don't worry about being in an unlady-like position. You will be told to spread 'em, pull your bits taut and hold your legs over your head. The professional waxer has seen it and heard it all. (Seeing embarrassed clients and hearing the screams of pain, that is!)
Having said all this, if you can, have it done in the comfort and privacy of your home.
As for the process, start off with hair about 1 cm long. If it's too long, it will make the job even more painful. The waxer will apply some talcum powder for better grip and wax a small area at a time, usually from the top then downwards. It takes about 5-10 mins and when it's over, treat yourself to (perhaps another) stiff drink or treats. You're smooth, soft and survived!
The area will be red and tender for a day or two. This is normal. Good luck!