To set up a proper Day and Night Cycle, you will need two things;

• A Day Global Lighting Preset
• A Night Global Lighting Preset

To make lighting presets in your Map Editor, scroll down in your Map Properties until you find Ambient Light and Directional Light settings.

You can then change these settings however you want. You WILL have to save it globally, though. To do that, scroll up and find the Lighting Presets dropdown. It looks like this:

Next, click the “Save Current Settings As Global Preset”

Then make your Day and Night light presets. This can be anything you think of! It doesn't have to be day and night lighting presets!

After you have your lighting presets, go to your Game Configuration. After that, go to your Gameplay tab and click “Day/Night.” You should see something looking like this screen:

After you have everything set up, make sure you have “Use Day/Night Cycle” turned on from the Map Properties tab like so:

After which you have your very own Day and Night Cycle set up!