Pull ups are hard. You are hauling your body against gravity to a bar using your arms and upper back.
This is not a move anyone is born performing. It takes time, energy and effort.
In this video, I layout a realistic progression. It could take a month to a year to achieve this based on your starting strength levels and persistence.
There are enough tutorials out there that incorporate bands, so I gave that approach a skip.
There's a move called an inverted row that serves as a good bridge that I will cover later this week.
If a pull up is something you've wanted to do, this is a reasonable guide. The lack of brevity is because I wanted it to cover all the bases and be realistic.