I suggest you take some time to do some research in this area. With running: you should start with walking 30 mins a day, build up to a jog and running 20 mins. With water: drink as much as you want its very good for you. 2 litres a day. With food: stay away from fried foods and takeaways, or candy or high fat foods like chips/cakes/cookies/chocolate. Eat more fruits and vegies and lean meats. You sound motivated, and I think with the right mindset you can achieve this :-)