If you would like to look better and improve your health but have no idea where to start you're in luck.  What I would recommend is a simple program of two bodyweight exercises, the bodyweight squat and the push up.  These two exercises were chosen because they both involve large muscles that will expend lots of energy, thus burning lots of body fat.  This program assumes that you are strong enough and healthy enough to do these exercises with no problems.  As always check with your doctor before engaging in any type of exercise program.

It would be best to start just after you awake in the morning for two simple reasons.  First, when you start just after awakening you get your day off to a positive start which will give you forward momentum to continue making good choices throughout the day.  Second, when you exercise first thing in the morning your body is depleted of its glycogen stores and the energy required to complete the workout is coming mainly from stored body fat.  

You will be performing these exercises in a superset which means you will be doing one set of squats immediately followed by a set of push ups.  Your chest, shoulders and arms will be at rest while you're performing your squats and your legs will be at rest while you're performing your push ups.  

Following are the steps for the bodyweight squat:

Step 1:  Stand with your feet shoulder width apart while pointing your toes slightly outward.  

Step 2:  Slowly bend at the knees while keeping your weight focused on you heels.  Make sure that your knees are aligned with and track over your toes throughout the entire movement.  Keep descending and move your butt back as if you were sitting down on to a very short chair.  Squat down as far as comfortably able.  

Step 3:  Pause in the bottom position ever so briefly and reverse the motion until you are back in a standing position.  

Step 4:  Repeat steps 2 and 3 for the recommend number of repetitions.  

Following are the steps for the push up:

Step 1:  Begin standing with your feet shoulder width apart.

Step 2:  Bend forward, put your hands on the floor with your palms down and walk out with your hands until your legs and torso are straight and your hands are on the floor directly underneath your  shoulders.  At this point and throughout the exercise the only parts of your body that are in contact with the floor are your hands, the balls of your feet and your toes.   

Step 3:  Slowly bend at the elbows while simultaneously keeping your elbows tucked in close to your torso.  Lower yourself to the point that your chin and your chest are just above the floor. 

Step 4:  Pause ever so briefly in the bottom position, then reverse your motion pushing yourself away from the floor until your elbows are completely straight.  Remember to breathe naturally and focus on proper technique.

Step 5:  Repeat steps 3 and 4 for as many repetitions as you desire.  

If you have not been exercising on a regular basis but are able to perform this short circuit without any difficulties I would recommend starting out with two to three sets of each exercise for 5 repetitions per set and gradually increase one or both the number of sets and/or the number of repetitions per set.  This will allow you to start exercising without becoming too sore.  As you become better conditioned you could aim for something like 20 squats and 10 push ups per set for 10 rounds which would put you at 200 squats and 100 push ups for the workout.  

With minimal rest and a brisk pace you could have this workout done in less than 20 minutes while getting yourself off to a great start for the day while improving your health and appearance.