That is not really how Fiwfans work
Usually you're the one who need to go to their hotel/mongering place.
They are mostly working with agents who place them in a hotel, that's why you can find multiple girls under the same hotel.
Everything is pretty straightforward when it comes to booking one :
1. you add the Line that is showed on the girl's profile
2. you'll likely get an auto messages with picture of the girls + the "menu" to choose from and where she is located
3. tell the agent what time you want to book and what you want 1 hour/1 shot
4. he/she will send a recap message and ask you to confirm.
5. send a message/a pic when you're downstairs
6. he/she will reply with the room number
7. enjoy your punt
I would say the pictures are 70/80% accurates.. so it's sometimes a hit and miss.
enjoy!