Building up a muscles will not happen in overnight. We need follow all the dietary and fitness steps.
Regular diet will keep you healthy and helps you to build a muscles. Proteins supports well for muscle growth. Try to take at least 1 to 2 grams of protein for every pound of body weight.
Drinking adequate water every day will helps you for muscle growth. Also we need to eat regularly at times. Eating meals with contains high proteins which helps you to reach your goals.
Banana, eggs and milk contains high proteins. Try to add this diety food in your regular meals. Also add peanut butter for protein supply at regular intervals. Add fat consuming foods such as fish, corn, cashew nuts , almonds etc., Add vitamin capsules for supplementary purpose.
Secondly, Exercising.. A good diet is required for your body to be able to maximize your potential, but there's no potential at all until you start the process of tearing down your old muscles and rebuilding them bigger, bulkier, and stronger. Before you begin any exercise routine, whether it is a simple jog, or a 300 pound dead-lift, start with a low intensity routine designed to warm up all the muscles you're about to work on. Not only will it help you get into the right frame of mind, it can help prevent injuries. You should never stretch a cold muscle
Work your whole body The more muscles you use when training, the more hormones you will produce, which in turn stimulates muscle growth both while you exercise and for the entire day.
Give all muscle groups equal attention, such as five sets of rows after five sets of bench presses. This will encourage balanced training, growth, and flexibility.
Compound exercises such as squats, dead-lifts, presses, rows, and pull-ups use a lot of different muscles.
You can work the entire body in each session, or divide your sessions between, for example, the upper body one day, and the lower body the next.
Get your rest. Your body needs time to recover, and to repair (build) your muscles, and to do that you will need at least 7 or 8 hours of sleep a night. Avoid caffeine and alcohol for deeper sleep.