There is a second video that is supposed to cover breakfalls, but I haven't seen it yet. There are a couple of people at my club that are very good at them.
My understanding is that the way to start is to learn the forward and backward wide-leg 'rolls' that you see in the first video, as the breakfalls are mostly modifications of those, with a few quirks and tips that are related to particular situations. To learn it all, I think you need an experienced teacher... maybe several. I got a lot of tips on how to do it with no luck for a long time, then one particular instruction about visualizing where to aim my 'back hand/arm' set me on the path. I have learned how to do a fair chunk of the falls as exercises, but have a long way to go with doing them on the fly, being thrown.
It's actually a dangerous period, because uncertain falls 'in between' my old traditional style and the new style often prove awkard and painful. I seriously pulled an adductor muscle a few months ago, and the way I was throwing myself into the transition to wide-leg ukemi is a prime - though maybe only partial - suspect. Though mostly functional, the leg is still not completely healed 3 months later, and I had to abstain from ukemi, running, and heavier squatting/lunging for basically 2 full months to get the healing started. Now I'm trying to incorporate the new falls more cautiously.