welcome to the forum. i dont know exactly what you mean by "shadowing" but you can turn on the suns shadow by going to view menu then click on shadows. but if you want to adjust the shadows, you can do to windows > shadows, then an option box will appear where you can adjust the time and date of your scene. you can also turn on the shadows this way by checking the display shadows box.. ^^v
Although if you only have the free version I think the sun is set as if you were in Boulder, Colorado and can't be changed, so you have to buy the full version if you want to use it for sun studies. If just you want to make your model look more real it is plenty enough!
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