Oh Remy's video is just as good, but you would have found my timestamp a bit confusing ;)

You're welcome :)

Night effects cover the entire area, so they reappear beyond the screen. However, when you save your map as a bitmap export (Save as... in the File menu) you will only be rendering the area of your drawing, so you won't see any of that.

Have you followed the video or done your own thing?

If you followed the video, when you added the Wall Shadow, Point Light Finalize sheet effect there was an option to pick an alternative colour for the shadow. In the video Ralf picks a dark blue shade instead of black. At around 9.19 minutes in that video Ralf then turns the shadow transparency up to 50 percent the The sun settings, which you can get to by right clicking the hourglass on the left and picking Global Sun.

Have you done it that way, or a different way?

If you don't need to do anything more complicated than what you just described in your last comment, Remy (Monsen) is right. There should be enough information in the User Manual.

The Tome would only be necessary if you wanted to make symbols that were considerably more complicated than that.

The User Manual gives you the basics. The Tome provides the masterclass.