I need some main Ideas of Being There ???

Hi, really what you are looking for are themes.

Television vs reality- Chance sees the world through the filter of TV. Television of course presents an illusion to us. Things are contrived and often made up, reality isn't.

Death and re-birth - Chance looks through the void of death after the old man dies, Through this Chance must actually experience the world hence a re-birth.

I saw this so long ago when I was a child but this is what I remember. Hope it helps.