The giant Apse kit is designed to work with other kits from Forsaken Ruins range.
NOTE: Due to decorative buttress placement, only the spiral stairs will join with the Apse (unless you leave off the flying buttress from other pieces)
MDF kit supplied un-painted and un-assembled.   Instructions can be downloaded above as a PDF document.  We recommend using PVA glue to assemble the kit.
If you would like to have a go at adding your own windows to the Forsaken Ruins set, the vector files for the window outlines can be found here: 
ForsakenWindowsVectors.zip The .zip contains .ai .cdr .dwg and .pdf vector options.