When trying to build muscle it is critical that you consider both your workouts and your diet.
Ignoring either of these factors will set back progress considerably and leave you fighting to make even minor changes to your physique.
You should begin by thinking about what you want to achieve.
This could be a desire to lose a few pounds and get in shape, to lose a lot of weight and build up a muscular physique, or to put on weight if you are particularly skinny.
If you are a little bit over your target weight then adding in some weight training days along with some running or cycling work should work well for you.
The addition of weights means your body will be pushed harder and muscle is important in burning fat quickly.
If you are much bigger than you would like and want to turn this into muscle then you should follow a routine of heavy weights along with cardiovascular work.
As you push yourself hard you should see the pounds fall off.
If you are skinny and actually want to gain muscle mass then you will need to do weight training but no cardiovascular work for the time being.
You probably have a high metabolism so any exertion will see the pounds fly off.
Along with these training sessions you need to consider your diet.
If you are overweight then you should be following a healthy diet and cutting back on your calorie intake.
Make sure you have lean chicken and fish to develop your muscles.
If you are looking to develop muscle mass then you will need to eat more.
You may find that you start to add some fat to your body but you can burn this off later with some running or cycling when you have developed your muscle.