Most meetings happen at the escort's address, almost always with a door opening straight onto the sidewalk or a short landing with no doorman. If you'd rather use a hotel, there are none inside the neighborhood: that's solved a few blocks south, already in the central area. The third format is her coming to your accommodation, something requested quite a lot by people arriving from the interior.
The first message should be specific: who you are, which day and time you're after, how long and what kind of meeting you have in mind. The reply will tell you whether there's a slot and what terms she works with. You always talk to her, never to a third party, and that direct back-and-forth is the best way to know who you're going to meet.
Almost everything is handled by appointment and in fixed slots: since the units are small and the walls thin, nobody improvises or overlaps times. Arriving on time, neither early nor late, is part of the deal. And if the plan falls through, giving notice costs one message and leaves the door open for another day; the area is small and word gets around.
As for profiles, independents who run their own diary predominate, of varied ages and styles, Uruguayan and foreign. The services run from the short meeting to the long stretch with conversation, deep-tissue or erotic massage and the GFE format, closer and unhurried. Every ad details what it offers; if something isn't listed, ask about it beforehand and don't take it for granted.