Have you seen Will Smith's I am Legend? From the movie you will see that the actor have a very good physical form.
You can attain the same fit body too by working out the right way.
Doing it improperly may not only cause injury but it would also drag the duration when you will notice the changes.
There are two types of exercises that you should consistently do.
First, you should always do aerobic exercises and second, you should not forget to do some spot training.
The aerobic exercises would help you shrink fats and thus reduce weight while the spot training is an effective way to strengthen and increase our muscle mass.
If you are just a beginner, it is better for you to take it easier because you would certainly feel some muscle pains.
Increase it gradually because the body can get used to the program and you would not be progressing the way you'd probably want to.
As for the duration of your whole program, take into consideration that you need to work out for at least 30 minutes until you start burning off the fats.
From there, how long would you do it depends on you.
When you plan on using some weights in your workout, remember that you should go for those that would not be too easy on you yet at the same time make sure that you would finish the whole set.
Always give time for you to workout.
There are many benefits from doing it aside from making sure that you look really good.