The Ithillian Sky Port is made of a number of pieces, which are designed to be assembled as individual sections before being glued together as one piece.
Assembling the base level
For this section, you will need pieces Base-A, Base-B, and Base-C
Put the now fully-assembled base level aside for the moment.
Assembling level 1
For this section, you will need pieces LV1-A, LV1-B, LV1-C, and LV1-D
Put the now fully-assembled level 1 aside for the moment.
Assembling level 2
For this section, you will need pieces LV2-A, LV2-B, LV2-C, and LV2-D
Put the now fully-assembled level 2 aside for the moment.
Assembling the sky port
Gather together your fully-assembled base level, level 1, level 2, and the sky port top (level 3). Glue the sections together in order, on top of one another, to complete the sky port.
The Ithillian Sky Port can be purchased here.