Pull ups or chin ups are a great exercise to start with. You can add weight to your body after your own body weight has become too easy for you to lift.
Chin ups are done with the grip supinated (palms toward you).
Pull ups are done with the grip pronated (palms away from you).
The main muscles work with this exercise are lats, biceps, brachialis, pectorals, upper back, abdominal wall, and forearms.
You have several grip options. You can hold a staight bar with a supinated grip or pronated grip. (palms toward you, or away). Find a grip spacing that is comfortable. Pronated grips should be about 2-3 inches wider that a should width grip. Your forearms should be vertical when your in the contracted position.
Using two parallel handles may be more comfortable but be sure they are not two close together. They should be a little wider than your shoulders.
The bar should be high enough so that you can grab the bar when standing on your toes. The best height will allow you to pause for a few seconds by taking your weight on your toes. This will allow you to rest your grip so you can continue your last few pull ups.
STEPS
1.Pull your body up until you touch the bar to your collar bones or lower on your chest.(parallel grips will be more difficult to pull low)
2. Fully contract your lats by pulling your shoulder blades down. Your back should be arched at the top of the pullup.
3. Inhale on the way down. You can inhale on the way up, or briefly hold your breath and exhale at the top. (only catch your breath at the bottom position if your briefly stand or kneel).
Never relax or stretch in the bottom position. Never drop down from the top position. You should control the descent.
Keep your eyes focused upward.
Keep your head forward and tilted back. Do not throw your head back.
Keep your shoulders tight.
When you are ready to add some weight you have a few options.
A shoulder harness or belt designed for hanging weights.
Or tuck the handle of a dumbbell under your lifting belt.
Or use a strong piece of rope to hang dumbells or plates from your belt, either in front of your thighs or to the rear.
This is a parallel grip. It may be more comfortable. However, it will be more difficult than the supinated grip or pronated grip to raise your body as high.