the following as a 5 min intro video to one of the techniques :

- https://www.youtube.com/watch?v=FP-dNd1xTcs

if you want to learn more: https://yogananda.org/practice

I read the book it was pretty good. He talks about his experience and a lot of history of breathing techniques and at the end of the books has basically a reference guide and things to look up. Might be worth looking for a digital copy to just cut right to that.

In the article he says he inhales for 5.5 seconds, then exhales for 5.5 seconds.

If you look up the method he states on YouTube there are videos. I also just described it in another comment.

You have to buy their book to find out.