Ok, ok, girl to the rescue.
Well, I only went to one in Japan, but I have been to a few in Korea, and its very very similar.
Basically when you go in, you pay your money, they give you a towel (but take your own just in case they dont... I got caught out in Japan without one and had to buy 2 that were really thin, and didnt dry me much).
Some have shampoos and body washes, but it pays to take your own, as well as all your normal bathing items.
Oh yeah, you take your shoes off at the entrance, and put them in a little locker, then take the key from the locker to the front and pay, then they will give you a key to a bigger locker inside.
So enter the womens changing area, take off your clothes, then take your towel, and washing things into the general washing area, after locking everything you dont need into the big inside locker.
When you are in the general washing area, there are sit down showers, or standup showers, wash your body clean. Pays to have one of those scrubby towel thingees to get all the dead skin off. If anyone would be watching you, it would be now, but I havent noticed it. They will be checking to make sure you're clean enough to get into the baths! (just kidding, but maybe it happens?)
Then after a thorough scrubbing there is usually somewhere (a ledge or shelf) to put your shampoo and stuff on while you are bathing.
Generally, but not always the temperatures of the pools will be indicated in degrees celcius, otherwise make sure you check with your toes before jumping right in!
Feel free to get in and out of all the different baths, outside baths are nice and relaxing and even the super hot ones are bearable with a nice cool breeze.
Dont feel too self concious, they have been bathing like this since the beginning of time... you will most likely only be uncomfortable for the first 5 minutes anyway.
I have two tattoos, and have never had problems with them, also I went into one once severly sunburnt, so bright red and WHITE and nobody even looked then.
Mothers usually take their sons with them into the baths, just because its safer than them going by themselves into the other pools, but once again, they wont be staring.
If anything they just get in your way when they practice their swimming.
When you're done, you go back to the ledge, get your shampoos and things, and re-wash. Then dry yourself before going back into the changing area. In the changing area there are communal face lotions, hair products and hairdryers, so you can leave looking more like a million dollars than a drowned rat
Enjoy it! Its so wonderful and relaxing!
If you have any more questions feel free to ask!