Is this download okay?

FSX British Airways Airbus A380 Demo Version

I was going to give it a fly, but stalled.

What stalled the aircraft or the sim.
If it was the aircraft then it was a fault in the loading, although i don't know what you mean by stalled.
Engines quit, it froze??
If the sim crashed or is low on FPS then it's your machine.

If you are talking about the aircraft ingame stalling, the A380 has a high chance of stalling if the fuel tanks are full. Try setting them at 80%.

I don't think the plane will accept any throttle over 50%