The best advice I can give is to not try to revamp everything all at once. People that try that rarely succeed long term. Sure, it can work in the short term, but the real goal has to be retraining your body and mind how to be healthy.
As such, I would urge you to pick something small to start working on today, or at least in the morning if you want to start fresh. This needs to be something so small as to almost be inconsequential. The reason it needs to be small (aside from helping with compliance), is so that your body and mind don't actually recognize that you're "dieting" or "working out". Continue with that one simple thing for a couple of weeks until it's become a new habit. Once that new habit is established, you can then make another small change. Just keep making small sustainable changes until you reach your goal.
Yes, this approach is very slow, certainly much slower than drastic diet and exercise plans that promise quick results. Remember, what does it matter if you lose all the weight quickly if when you get there, you can't maintain the weight loss?
Your real goal needs to be learning how you personally need to eat and move for long-term health. What that looks like is different for everyone, so no one here can tell you "eat this way", or "do these exercises" and you'll find success. It has to fit in with your unique needs, tastes and abilities and only you know what those are.
If you feel like you need more guidance than that, I'd suggest seeking out professionals such as Registered Dietitians and Certified Personal Trainers. to help put more detailed plans together.