I'm not able to figure out what exactly to select and launch.
What is that you can't exactly figure out? The person in the other topic had the same question as you and the solution is simply change it position back to the beginning of the scene and also set the health back to 100 if the player got health and such.
In case you don't know the position of the beginning, select the player in the editor and you should see the X and Y position on the left. Simply change the X and Y position of the player back to the position you see in the editor on collision or whenever, however you "kill" it instead of deleting the player.
But in case you want to start the whole level from the beginning, simply use the change scene event to start the same scene again.