This drill will help whether you want to get your 1st, 5th or 10th pull up.
In all movements, the strengthening phase is when muscles lengthen. This is the ECCENTRIC phase.
So use a chair to stand on to bring yourself to the bar.
Slowly lower yourself from the bar to a count of 4 (or more).
If you can’t hold your full body weight, provide support by taking weight on one foot.
Gradually lessen how much support you give yourself.
Test your pull up strength after a week or two.
Will you try this?
Here are other video tutorials that will help: