When the application opens, the time is set to noon. You can set the slider to different times of the day and see how the natural light decreases or increases.
To add an illuminator, click On in the menu to the left and select either 50° or 100° beam angle.
To move the illuminator sideways or up and down, click the arrows.
To better visualize the placement of the illuminator, click the bottom thumbnail on the right.
To change between white light and IR light, select the colored or black-and-white thumbnail respectively.
Play around and see how a poorly installed illuminator lets the shadows cover the man in the shade or how brightness and glare makes the object invisible. And, if it's important to see colored details like the sign on the man's t-shirt, what type of light should you go for?