If you visit your local gym you will notice that everyone there is trying to build muscle. Most are using these high technical machines that use resistance. In fact using free weights you will be able to build muscle quicker than these machines.
To build muscle quickly you need to do resistance weights that use all the major muscle groups. By doing hundred of bicep curls you will not achieve much muscle mass as these muscles are relatively small.
In fact you should work on you back, chest and legs as these are the three major muscle groups and working on these you will utilize more muscles than you would ever do by training your biceps.
To work on your chest, the best exercise would be your bench press. This exercise is by far the most effective to build muscles. Work to do 3 sets of 8 repetitions per exercise. If you do more repetitions or sets you will work against you as you will work on endurance rather than muscle strength. Therefore do not be tempted to work more and allow your body to rest adequately.
To work your back and legs then the barbell squat is the number one exercise. This exercise works your entire body and will get most of your muscles involved in the exercise. This type of exercise will allow for fast gains in muscle mass thought out your body. Form and posture is key to the barbell squat and if poorly done will injure your back. Do also lift the barbells with the safety rack and nt directly off the floor as this will also hurt yourself.
If you do correctly and eat well you will see the improvements in your muscle mass and strength within 8 weeks.