Now that you can make a slip knot
you need to learn how to hold the yarn.
There are many different ways to hold the working yarn. The goal is to control the tension of the yarn as you work with it while still having fingers left over to hold your work in progress.
This is how I do it:
Starting close to the hook, and working loosely, hold your hand palm up and bring the yarn up between your ring and pinky fingers:
and bring it down over the pinky.
Wrap around the pinky then pull the yarn up between those same two fingers again:
then pull the yarn up towards your other fingers.
Bring the yarn down between your pointer and middle fingers and wrap it up and around your pointer finger:
Then hold your work in progress between your thumb and middle finger:
This will allow you to control the yarn by moving your pointer finger up and down as needed, and holding the rest of your fingers splayed apart or held close together to make the yarn come faster or slower, respectively.
Experiment with it. Some people find that simply holding the yarn in a loose fist does the job just as well.
I encourage you all to post pics of how you hold the yarn. What works best for you? The more options the better, I think!