There are many ways to accomplish lighting effects in Dimension. You can use Environment Lights as preset lighting setups, you can use Match Image to automatically light your scene and match a background, or you can create your own custom studio lighting setup using directional lights.
You can add or remove additional lights. Select a light in the Scene panel then use the delete key or action to remove it. To add a new light go to the Starter Assets panel and click one of the directional light presets —circle, square, or sun, to add another light.
There is no hard limit on how many lights you can add to a scene, but only four shadows are visible in the real-time canvas view at once.