Going to just answer you directly, without reading other posts...
To start out, I use to be 250lbs, not down to 185lbs to 195lbs...
100% it is want you eat, you can go work out, but there is no meaning if you want nice tone. not changing you diet you'll muscular with a beer belly and bulk, but never cut or lean. Your going to need a lot of determination and motivation! Take lots of progress pictures and read a lot of articles on like "bodybuilding.com" great resources and ideas for workouts...
Here is my routine... Eat many small rich protein meals throughout the day, I do about 4 meals and small filler snacks like yogurt and such. Stay away from all the saturated fats and sugars and eat more lean protein, fiber, calories don't matter unless your losing weight, I balance with weight lose and muscle mass, so I can't count as much.
For a simple idea for working out, always do at least a mile cardio before or after the exercise, join a gym for motivation, dedicate each day of the week to a certain body group, chest, legs, back, shoulders, arms, you can do more than one if you really that motivated and have that much energy to keep going. Abs I do while stretching before exercises and do a more serious core exercises on my off days or rest days. I have a pool at my gym so I add that to the list.
You just need to do your research into exercises and what works for you, not everything someone says will work, it might for them, but it might not for you. Find your sweet spots. But make sure you give up sweets and junk, and look at those people at the gym who have the body you want for motivation and see how hard they are working! Thats the best advice I can give...