Lol,
Yes. Maybe you can help me understand a few things. Is it possible to have "air" (oxygen) and still be in a near vacuum that is strong enough to float in? Also, I thought sound did not carry through a vacuum. I have tried to find experiments on YT that show how these things are done but cannot find any.
Well RealScientist already explained it.
The ISS does not float on a vacuum, like a boat does on water. The ISS is only moving through a vacuum. If it would stop moving, it would just start to fall to earth. That is why the ISS has a certain speed to keep it nicely flying around the earth in an orbit. That is called the orbital speed.
It is perhaps quite abstract to think about it, but because the forward force is equal to the downward force, the ISS flies nicely around the earth. I made a small diagram so you understand it better, perhaps. The black line is showing you what the ISS is currently doing. If at one point the ISS would be suddenly stopped, the ISS will follow the green line. It would just fall down to earth. If the speeds get lower gradually it will follow the red line. If the ISS is going to accelerate it will follow the orange line. That is why they keep the ISS at a constant speed of about 28,000 km.
As for the inside of the ISS it is filled with air, just like we have here on earth. The hull of the ISS is strong enough to contain the air so it does not break. The same like airplanes maintain a higher pressure on the inside if it is flying at high altitudes. One difference with airplanes is that they regularly take off and land, so to reduce the constant different in pressure, the pressure on the inside is maintained at around 8,000 feet. This way the stress on the fuselage is less, lowering the risk of metal fatigue.
The ISS does not regulary land or take off, that is why it can maintain the same pressure as on sea level. The hull is made strong enough to withstand the pressure pushing from the inside.
On videos made aboard the ISS you hear sound. The sound just travels through the air that is inside the ISS.
You are right that sound does not travel in a vacuum. Once astronauts are outside, they would not hear the other one scream if he would do so. He would hear himself though, because he is in a space suit, which again is filled with air.