for example: https://youtu.be/QsCfx-jjS0U
You can see white circle light texture in this video. I followed theese steps but my light texture is invisible
The light will only become visible, if you have some kind of texture behind it. So create a new scene of type TextureRect, set its texture-property to a cool image and then add your player-scene as a child. Now you should see the light effect applied on the background image. Also check out this part of the documentation.
Yes sir you are right but isnt there any other way like World Environment ? Or should i do a infinite background to see it always