Pull-ups are a great exercise for strengthening the upper body, particularly the back, shoulders, and arms. If you're new to pull-ups, here are some tips for getting started:
Find a pull-up bar or other equipment that allows you to grip the bar with an overhand (palms facing away from you) grip.
Stand beneath the bar and reach up to grab it with your hands shoulder-width apart.
Engage your core and keep your feet off the ground as you pull your body up towards the bar. Keep your elbows close to your body as you do this.
As you reach the top of the movement, your chin should be above the bar.
Lower yourself slowly back down to the starting position.
It's important to start with a grip width that allows you to do at least one full repetition. If you can't do a single pull-up, there are a few options to help you build up your strength:
Use an assisted pull-up machine or resistance bands that provide additional support as you perform the exercise.
Try doing negatives, where you jump up to the top position and then slowly lower yourself down. You can also use a chair to in order to get up to the bar.
Do other exercises that target the same muscles, such as rows or lat pulldowns, to build up your strength.
Ideally you should be practicing them every day for approximately 5-10 minutes each day.
As you get stronger, you can gradually reduce the assistance and work towards completing unassisted pull-ups. Remember to always use proper form and start with a weight that you can handle to avoid injury.
If you'd like to watch a video that demonstrates this practice, you can find my YouTube video no pushups here.