TCANNO
It look like you are motivated or you would not be here, good for you it is the first step.
Put all behind you the you learned before and take it one step at a time.
Track you food is going to be a must and then move on to short belts of exercise, 10 minutes a day is a good starter but make sure you do it every day.
You could join my 10 minute a day exercise team as you will find plenty of friends / help there. Link on my page