I think the first thing you should do is eat right, and maybe walk a little. That will get you started. I don't think there is any "quick" way to get abs and pecs. You have to take it slow. Don't be too hard on your body.
Again eat well. Try to eat less sugars, more things that say "low trans fat" on the package and less things with partically hydrogenated something (that can be found on the back of the package, ingredients).
Don't walk too much and get too hot. Be sure to carry just enough water when walking. Try walking to not-to-far away places such as mailboxes (if you live in a appartment complex) or library; maybe even school.
Soon you can lift weights and have hottness build up