The Floo Network System

This model shows the travel between the Weasley's house, the Burrow, and dark magic items shop, Borgin and Burkes. 

Here I try to capture Harry's struggle. This model may not be the most detailed, but it makes up for that in mechanics.

Here is a video on the mechanics- 

So how these mechanics work- On the roof the the Burrow's fireplace, there is a small slot where you can insert "ash" or 1x1 circular, black plates. (These can only be inserted when Harry is in the Burrow.) When You spin the model to face Borgin and Burkes, it will then drop the "ash" into the fireplace, replicating the moment when Harry crashes into the shop. *That's why the ash falls*. The ash will only fall when Harry is facing Borgin and Burke's side. That is the special part of the mechanics that makes up for the architecture. 

*Harry Potter and the Chamber of Secrets*

Comment with any questions, and I will do my best to answer fast.