The general (basic) routine is:
You meet up with the girl in the reception area. You may get to pick from a lineup, or in a smaller shop you just get the next girl in rotation.
She will take you to the room, you will tell her how long you want to stay and pay her the shop massage fee (usually $40/30 mins, $50/45, $60-70/60, $90/90).
She will then leave the room while you get undressed. If you are shy and/or not sure about extras, you can leave your underpants on, but otherwise take it all off.
When she returns, she will tell you to get on the table, you should start face down so she can (pretend to) give you a back massage. At around the half-time mark she will discuss "extras". These will usually be $20 for a straight HJ, or $50 for naked (this could be just top off, or up to fully nude - ask the girl what she will do. Sometimes she might offer a "body slide", but in many cases this is just giving her tits a quick wobble over your torso and cock). If she asks for more than this, you should haggle. Most girls will accept payment at the end of the session, but some may ask for it up front.
She will then give your cock a quick dousing of baby oil and try and get you off. Her skills and attitude will play a big part in the quality of this service.
Once this is over, you may get a bit more massage to fill in the rest of time available. She will clean you up, maybe a hot towel to wipe off the oil, then leave you to get dressed.
She should then come back to collect her payment, and escort you to the entrance.
The quality of all this will vary from girl to girl, and how well you connect with her. Things will usually get better if you become a regular customer.