The sun/moon icon at the bottom left of the "scene" shows whether you've arrived in the city by day or night (and eventually, morning or evening as well) local Herculaneum time. It gets dark on those streets late at night -- but in most locations you can change the time of day by clicking on the icon.

To read the journals of our protagonists, click on the covers of their notebooks to see the table of contents. Clicking on the chapter titles will transport you to the area of the city relating to the entry. A closed notebook cover indicates that the chapter is not yet online.

As you walk around, if you see something of interest -- a building or an object -- try clicking on it. You may be able to move closer to it; you may even be able to "pick it up" and examine it. Over time, more and more items will become "clickable."