Click using the left mouse button on joints and use the gizmo to manipulate the models and lightsource.
Hold down the right mouse button and drag to rotate the camera.
Pan the camera using shift + right mouse button, or arrow keys.
Scroll using the scroll wheel (or 2 fingers on trackpad) to zoom in and out.
Change models with the icons on the bottom right of the screen.
Manipulate the light intensity, toggle the joint indicators, undo changes and reset the models using the icons at the bottom left of the screen.