Changing direction
Hold down the left mouse button and drag the mouse.

Moving the camera
The easiest way to move is to scroll, and you fly to the mouse courser
Some users prefer WASD+QE to fly.

Rotate around object
Hold right-click mouse button to rotate around an object (360 view). Remember that the area where you point the cursor will be the center of the rotation.

Up, down, right and left
Hold scroll mouse button to move up, down, right and left

Selection
To select an object left click.

These settings may be changed under Adv. Settings -> Camera -> Controls