If the planet were quite hot as @Formagella describes, say around 80°C, there likely would be no (constant) bodies of water and no steam. Whatever water the planet had, would mostly be in the atmosphere. If it's a lot of water, that means terribly bad storms, floods, F25 hurricanes, far worse than anything we see on Earth. If it's little water, it's going to be a very desolate place, mostly a barren, desert world.
The inhabitants could live in the mountainous regions, where the elevation reduces the temperature. Perhaps even above the "bad storms," on land or on airships. But there are some issues with these. It's hard to grow food at high elevations, mainly because it's too cold for us, but also because there's little flat, fertile soil. On airships, hydroponics would probably be used to reduce weight.
Since the "air" is going to be thinner at high elevations, so too will the water vapor content. So the "extractors" must be bigger and use more power. It is possible to disassociate water (H2O) into H2 and O2 by electrolysis. That too takes a lot of power. The good news is, a planet near it's star gets LOTS of solar energy, so sunlight (solar panels) are a suitable choice.
If many humanoids were consuming the oxygen, then twice as much hydrogen (H2O) has to go somewhere. Some of it could go to the airships to keep them afloat, however let's not forget the Hindenburg! On Earth, free hydrogen doesn't exist in the air. It either rises through the atmosphere and out to space, or combines with other atoms to form compounds. So for instance, if your (storming) atmosphere had nitrogen in it, then NH3 (ammonia) could form from lightning strikes, which is quite caustic and hazardous even at low levels. (It's flammable at higher levels!) Now if the inhabitants were intelligent and responsible enough to see ammonia levels rising and compensate for it ("ammonia scrubbers"), then it wouldn't be an issue. But that's more solar panels, more equipment...
Longetivity-speaking, if this civilization had lived and prospered there for a very long time, then the water vapor levels will drop as they are slowly consuming the vapor. So there would be legends and stories about the "really bad storms of old", and contrast to how much calmer the weather is now... and an uneasiness about the future, where the vapor is gone.
Also consider that plants here need sunlight, water, and CO2 (carbon dioxide) to grow. Sunlight, water, and water vapor aren't enough. Plants also produce oxygen. So the fact that this world has no oxygen, seems to infer that it has no plants. So maybe it should have oxygen, just very little of it, because it isn't a lush green world like Earth. Perhaps the inhabitants are in a rush to grow as many plants as they can, before the water vapor runs out?
The Earth only has 0.039% carbon dioxide in the air, but that's enough to grow all of the plants on the entire planet. And scare the "climate-change" theorists half to death.