On Roblox how do you change to background of a place to stars

First open the Roblox studio. Second in the explorer click on lighting. Finally, set the time of day to a time at night.

You can also do the same by going to lighting like above but then going to insert > Object > sky. From there just find decals that you like and use them as the sky giving you starts but also anything else that you may want in the sky.