You are correct Pilot, I forgot to say 'Whilst holding down the right mouse button'
The Right-Alt button allows you to move the scene left/right and up/down.
The Left-Alt allows you to rotate.
Whilst I'm about it:
Holding Crt-Left Alt and using the left mouse button does the same as the Right-Alt.
If instead you use the right mouse button, it does the same as the Left-Alt.
Planck