from another Amanda!
What kind of job do you have? Like are you busy constantly the whole time or do you have a lot of downtime? Do you have access to fridge/microwave/stovetop or oven?
I'd start out slowly- maybe count calories (they have a lot of free apps on the phone for easy tracking)? That way you can have a lot of options on what you can have and cannot have. You don't have to eat breakfast/lunch/dinner and/or snacks. Make your own rules! If you do snack, I'd try to make it whole foods like veggies, fruit, yogurt and/or cheese.
Without knowing your age, I'd put you down for around 1800-2000 calories per day and that is without exercise! As for how you should exercise, if you're a total newbie, start out slowly! Walking is a great start! Lots of free walk-at-home videos online.
Well, that's all I can suggest for now with the info you've provided.