I need help really bad: My teeth are in a bad situation and I need to get rid of this. (Photos)

My age is 18 and I have been fond of sweets every type not much now after realising my situation but In my early teens like 14 15 etc. And also I had no interest in brushing my teeths regularly. 1- I want to get rid of these brown spots on front of my teeths. 2- I want to get rid of these cavities on last teeths what will be the procedure and what do i tell my doctor to do in this situation I mean he knows also but what i go for?