Check out Iranian traditional wind towers. They used/use underground aquaducts, wind towers and thick masonary walls to stay cool.
Thanks for the Windtowers, Ken! They seem to improve my ideas of how to keep coolness. I had thought on having houses were the main floor is half underground for about the first meter.
For your story build from what you have, do the mountains have forests? or just stone? What is the social organization; nuclear families, extended families, villages, towns? What technologies have they mastered? Do they channel water, what do they use for power? What are the environmental challenges; heat? earthquakes? ultraviolet radiation? Does your culture draw on a current or past Earth culture? What art/craft are the people known for? How does their religion impact housing; altars, building orientation, decoration. What are the security requirements? Do they surround each house with a ten foot wall or not bother with doors and locks at all?
Mostly they have stone, but there are small forests and some fertile plateaus in higher lands. About the desert, I have asumed that is a Shadow Rain type of desert
There is only one large settlement that lies on high valley and is limited by a canyon with a river within and have several villages and towns around that were founded as military outposts in strategic places
The houses of the poorer people (farmers, servants, etc.) I thought of a design based on the Shabono of the Yanomami people:
While more prosperous people inhabitate invidivual housings
About military outposts, I have thought on trapezoid-like blockhouses looking down from higher lands
Their agriculture apparently is based on rotative agriculture to not overuse the few fertile high plateaus. They have mastered metallurgy, thanks to the abundancy of iron and other metals on the region and thanks to this, they expanded outside the mountain range, conquered the city-states from the glasslands and slaved their citizens, leaving them as farmers to work in the more fertile glasslands and builders of military outposts and walls wereas the citizens dedicate themselves to war, science and philosophy; specially war.
Their techonology is no more advanced that the 5th Century A.C., although they have watermills in most of the many rivers that goes down the mountain and ends on the canyon river and have managed how to create aqueducts to transport water, roads and stone bridges
Around their world, they are more known as a fierce and conquering race, when a boy turns a certain age, he (with the group that was born the same day) is exhaminated and must pass a series of tasks to see if he is fit and how fit is he. They also train females, but only to spying purproses in case of one of the 3 city-states tries to revolt.
There is no formal education, most of education is passed down by older brothers and sisters, a living grandparent, or an older man in the community. When one gets old enough, usually is accepted as a protegè in a craft. The closest thing to university are the monks in their academias. They are an agalmagation of preacher, philospher, mathemathician, inventor and sages
They are ruled by a king, the descendent of the first son of the god Sun and the moon Goddess; because the duality of their religion and essential philosophy (basically it is percieved that the day and the night lives inside each person, each one with their own pros and cons and that being "good" or "bad" is just a point of view) the kings are usually named if their were born in the dark season (rain season) or the light season (dry season) as Shadow King, Mirror King, etc.
Mirrors are sacred objects because they can multiplicate light and people, some larger rooms and the royal palace are lighted with a mirror system on the daytime
Earthquakes seems to happen rarely, but they do, and usually marks one of the large ages. The calendar is divided on the ages of the earthquakes, then they are subdivided on the reign of the kings, and then a year is divided on a solar calendar that each month is a lunar phase. Every seventh day is a rest day and a "week" is of 14 days.
I have chosen not to base this civilization on a existing one, but you can notice that I have taken things from several ones, I know what I have seems a little simplistic, but at least is not the same Generic Medievaland stuff, eh?