As everyone knows, pull ups can be kind of hard because, unlike the bench press where you can start out with lower weights and then build up over time, with pull ups you have to move your entire body weight from the get go. I've already talked about ways you can go about getting your first pull up. These include scapular pull ups, australian pull ups, and machine assisted pull ups. But the one that helped me the most when I was trying to do my first pull up is called the negative pull up. It's a really awesome exercise because it mimics the exact same range of motion you would have while doing a normal pull up except that you're focusing on the eccentric (or downard) portion of the movement. You can use a stool or even jump up to the top of the bar, then you more or less just slowly let yourself back down. Soon you'll be able to hold the negative for longer and longer periods of time. Here's a brief demonstration for you.
If you could do this maybe once or twice a week during your workouts it will really help you with your pull ups. It's just such a great exercise to learn how ro do.
Have a great day!