Get yourself use to lifting at first. If you've never been in shape before, you can easily exhaust yourself and you do not want to be discouraged. Take it easy at first and progress when you feel comfortable. Work on your upper body one day, and lower the next. If you're looking to getting 'ripped', do intensive cardiovascular work outs after lifting. This optimizes the burning of fat, thus, a toner look. I'd be worried about getting muscle mass though, because you don't want to task yourself like that just yet.
I wouldn’t eat to your heart’s content, if you’re looking for building muscle mass quickly. Yes, an increased intake of protein and complex carbohydrates will help, but don’t over do it. Eat lean meats, and if you need additional protein, then drink some protein shakes. Just remember you’re body will only utilize so much, and too much can be stored as fat (sometimes). Plus, your liver processes that excess protein, so don’t be hard on it.
And like others who have suggested, try a gym. If you can get a trainer, then you've got someone who can help you set and reach new goals. Yes, I know friends of mine where their parents see the bow flex add, order it, try it out, and then it collects dust in a garage. Going to the gym may be a little intimidating, but you'll see plenty of people there trying the gym out in worse shape than you. You've got to start somewhere.
Remember, you're not going to get really big soon. This stuff doesn't happen over Friday night. Working out is all about building a strong foundation. Once you’ve got that, you can take on new tasks to reach new goals. Good luck!