Fixing the gravity for laser puzzle game in unity

I'm working on a c# project and need an explanation and answer to help me learn.

Hello, I need some help making adjustments to my group laser puzzle game. The gravity still needs to be fixed since the gravity for falling is still broken when the player falls from the scene the game objects still float up into the clouds instead of the game objects just remaining in the scene. To be exact with the expected behavior it would be when the player is falling from the object they will perish once they hit the ground and have to start the level over . The game object in which the player was on say they are at level 2 or 3 it is not suppose to float up into the clouds even after the player falls from the object . The game objects needs to stay in place in the scene so that way when the player falls from the level they can start over and the scene will not be broken meaning the objects will not move when you fall from the level. Here is the require version of unity to download that I have to use for my courses make certain that your computer is capable of downloading it

https://unity3d.com/unity/whats-new/2019.4.30 .

I will give you the game file as well with we transfer soon

and I will need you to tell me how to fix the gravity as well we can chat on discord or you can tell me how to fix it in the chat as well. I need this to be done in 2 days and if you do not know what to do do not bid on this question at all. Also, keep me updated with your progress as well since the last tutor failed to communicate to me well and I am not sure what time zone you are from but I am from the united states.