How do I lower the saddle on a Scirocco bicycle?
The saddle is supported by the seat post which is inserted into the seat tube of the frame. At the top of the seat tube there is a clamp which holds the seat post. On some bicycles this is built into the seat tube, on others it is a separate collar. Undo the seat post clamp bolt, and the seat post should slide in the seat tube.

I'm guessing that the above is obvious and you have loosened the clamp, but the seat post is not moving. Seat posts are notorious for getting stuck as water can seep between the post and frame tube and cause corrosion. If the post is not too badly stuck twisting the seat can unstick it. Using a penetrating oil such as WD-40 can help also. 

If the seat post is really stuck there are many videos on YouTube documenting unsticking techniques.

If/when you do get the post loose, be careful to not overtighten the clamp after adjusting the saddle height. It's possible to damage the threads of the bolt or the clamp.