Start by cutting things such as Soda and try to walk more. Don't even need to set a time and date to go for a walk. Just walk to places you would normally drive to that are realistic. I started with a friends house. I visit him a lot, and would normally hop on the bus. I now walk to his house whenever I go. 10-15 minute walk, and I absolutely love it.
DRINK WATER DRINK WATER DRINK WATER
I know that it isn't much, but that is how I started. I was also close to 200 and I am 5'6. I just stopped drinking Soda and never set foot on an escalator or elevator ever again. After a while I did not even notice it. I did not start doing any sort of exercise until I hit 150. It is definitely great and will help a lot if you do it. All up to you.
Don't try to overcomplicate it by looking into different diets, exercise programs and whatnot. Everyone is different, and not every diet works for everyone. If you start one and it does not work for you, it will mentally break you. There is plenty of time to experiment later.
Just it and take it easy. You do not need to rush. If you have to determination, you will get there. There is no other outcome if you stick to it, plain and simple. Trust me