To work out how cultures might develop in a setting it might be a good idea to understand where they develop in relationship to specific locational elements and to each other. The majority of interest in this setting will be on the middle cluster of shells.The simplest way to draw a map will not be to scale, but through drawing an icosahedron net divided into hexes (the way this is drawn, the points of the icosahedron form pentagons rather than hexes).
Next we move "underground". Some sprays of colour highlight some important areas on this map. The genetic heritage of the Panaho race is known to be concentrated is a specific area, so this is marked in magenta. The shellbrood have established a major territory, and a few minor territories on this level, so they get marked in yellow. The hiveguard have focal points at each of the vertices, and I'll mark some streaks in cyan to indicate some pathways where they are commonly encountered.
Next I mark in some parts of the darknive that are known to be generally abandoned and decripit. These shouldn't be near the hiveguard territories, or near locations where established population exist, unless we're going to see some good story reason for the set up. Finally I'll add some towns.
But I'll leave it there for the moment.