Need help knowing and fixing my Samsung galaxy s6

hi i need help know whats wrong with my phone yesterday my phone died and i pluged it in a couple hours later it said it was 88% do i took it off the charger and tried to turn it on but it wouldn't so i pluged it back in and nothing showed saying that its charging so i left it pluged in at night when i woke up it still won"t turn on so if you know whats wrong with my phone and know what to do to fix it please help me