1  These are the parts you will need to test the fit of the dowel pillars.
2 Slot the Lower balcony part into the Main wall, do not use glue at this stage.
3 With one hand place Upper Balcony on top of the main wall and hold it there, with the other place in one of the 1cm diameter dowels on he pillar base and line up with corresponding pillar cap on the underside of the upper balcony.
4.Try to install all the others, (again, do not use glue) this can be tricky and may take a few attempts, you wil eventually be able to tell which of the pillars needs filing down (they are approximately 7.6cms tall)
You may need to keep testing out the pillars you have filed, it is a question of trial and error. If you file off to much you can build up the pillar with moding putty when it comes to installing them, but this should not be necessary.
Once you are happy with the fit of all your pillars, you can unslot the lower balcony and prepare to paint up all your parts before the final assembly.