For a beginner I recommend going with something simple that you can learn from.
To give an example of a plan that shows what no to eat, I liked this one a lot:
That plan has actually worked great for most people who have tried it, because it has you eliminating most of the junk. I would like to add to it that you shouldn't be afraid of carbs like how most people who try low carb diets end up. It isn't necessary. Most fruits and vegetables won't have enough carbs in them to make you fat, so there will be no need to worry about it.
Additionally, realize that calories will always count. And that's why I recommend paying attention to your fat intake. You probably don't need a ton of protein as recommended in that article. Instead, eat until you are full and you should be getting enough. You should be able to get plenty of fat from foods such as fish and chicken. But I highly recommend against adding extra fat to your meals beyond that in the form of oils, nuts, or cheese to give a few examples.
Additionally, foods such as egg whites can be a lot better than whole eggs while cutting simply because they are lower in calories. And that should be your main focus when trying to lose weight. You want foods that make you the most full, but are the lowest in calories. I'd check out the article on this website that talks about satiety. That should give you an idea as to what foods are more satisfying per calorie.
Now as far as what to eat, I can provide a few examples. Pretty much what you want usually is a lean protein source along with any fruits or vegetables. Starchy carbs such as oatmeal or sweet potatoes can be fine, but they are a bit higher in calories than some other foods.
Example plan #1 (low calories):
Meal 1 (lunch) - egg whites, oatmeal, and optionally any other vegetables or fruit
Meal 2 (dinner) - fish or chicken, sweet potatoes or brown rice, and optionally any other vegetables or fruit
Example plan #2 (extreme low calories):
Meal 1 - egg whites, any non-starchy vegetable such as peppers, spinache, etc..
Meal 2 - fish or chicken, any non-starchy vegetable such as peppers, spinache, etc..
Notice the difference between the two plans. All we did was find a way to drop the calories. And that would be the same difference as to how we would do things while trying to maintain.
When maintaining, you can allow yourself some more slack with things. You can have more fatty meats such as beef or pork if you like. You can have whole eggs. And you can even have other foods such as cheese if you want. Pretty much there isn't any reason why you should ever have to be afraid of any specific food as long as you have control over your weight. I might not recommend messing with this too much yet if you don't know what you're doing, but you really can eat what ever you want. The key is knowing how to maintain control, not eating junk foods too much or too often, and knowing when you need to cut calories.
Anyways, I'd probably recommend going with something more like meal plan #1 that I laid out. Meal plan #2 is probably not enough calories; i only included it to provide an example.
Also, as far as fat loss goes, I'd recommend going through periods of fast fat loss followed by periods of maintenance. The amount of weight you'll be able to lose pretty much depends on you and how long you can stick to it. Personally I had 40 lbs to lose and it took me 3 years to do it. Others I've known have been able to lose weight more quickly such as 80 lbs in 6 months.
It really doesn't matter how long it takes for you to lose the weight as long as you can maintain what you have lost. And that is the most important thing. I recommend weighing yourself every week to keep yourself in check. Give yourself limits from time to time. So for example, once you lost a significant amount of weight and if you don't have it in you to keep cutting, that would be the time to take a break. So for example, if you cut down to 220 lbs and didn't want to cut anymore for a while, that would be your new limit. At that point you would spend some time where you check your weight regularly to make sure your weight doesn't go above 220 lbs. If you go say 1-2 lbs over, you then do a short cut for a week before its too late. Do it like that and maintain weight for a while. Then once you get it in you to put in the effort to cut again for a while, do it. This is what I have done over the last few years or so and thats why I have been able to keep off all of the weight that I lost, because I kept myself in check. I even had a few times when I gained 5-10 lbs back, but then I fixed the problem before it got worse, and I eventually improved even more.
I also agree partially with what commander said about the workouts. You need the weight training to keep the muscle. The part where I disagree partially is when he says that diet is all you need for fat loss. I have personally seen many times in my own life where I was able to lose weight without doing any extra workouts such as running or anything like that. So the truth is that you can lose weight with diet only.
However, I've never had too much weight to lose. I mean, 40 lbs is a lot of weight to lose and it actually did take me longer than what I wanted. But on the other hand I had a friend who once was over 300 lbs and he had to lose almost 150 lbs real quick. He told me he ran every day. And he did agree with me that you can lose weight with diet only. But he also explained that if you have A LOT of weight to lose for health reasons, the only way you'll drop that much fat that quick is if you add in the extra exercise. Because that's the only way you're going to be able to burn that much calories.
I think in your case you have a lot more weight to lose than I did. However, I would only argue that trying to do the extra exercise isn't going to be worth it unless you have the time and will to do a lot of it every day. Because an hour on the treadmil done 2-3 times per week really isn't that much work, at least not enough to make a significant difference in calories. If you don't have that much time or you don't like it, then you'd be much better off cutting from diet only.