To perform a pull-up, you need a safe place :) If you have not a bar, be creative… and be careful! Grab with the palms facing forward. Your hands at a distance wider than your shoulder width.
Extend both arms as you inhale. This is your starting position.
Exhale, contract your lats and pull your torso up by drawing the shoulders and the upper arms down and back. The forearms should do not work.
Inhale and slowly back to the starting position when your arms are extended and your lats stretched.