Writing on WhatsApp from the ad is still the norm, but here it pays to do it several hours ahead. A message saying which day, which slot and how much time you have in mind is enough to close it. During the working day replies can be slow, not because nobody reads you, but because the afternoon agenda gets built early.
On the place there are three possible routes and it is worth settling it from the start: her apartment, your own lodging if you are passing through, or an apartment rented for the occasion. Several escorts in the area work all three, though each one needs a different amount of notice, so saying it in the first message avoids rescheduling at the last minute.
The local clientele drives certain kinds of request. Company for a work dinner, short meetings between leaving the office and heading home, massages to wind down after a long day. There are also people looking for something slower with no clock running, and several girls in the neighborhood work that way, with dates lasting several hours.
Bear in mind that the filter works both ways: on the other side they also decide whether your enquiry suits them. Writing with concrete details, not asking for extra photos or terms different from the published ones and accepting a no without pushing are what count most. Whoever coordinates well ends up getting slots that others are told are taken.