The best way I found to learn a standard was to have a copy of it and type it into a Word document. A big help is to have any related standard(s) or reference documents such as, in the case of ISO 9001, to have a copy of ISO 9000 and ISO 9004.
As I wrote, I made a spreadsheet so that every sentence had an entry for comments. When I was doing this stuff the internet wasn't yet. Now days there are thousands of websites, such as here, where you can read peoples interpretations. The way I did it was probably "old school". It's how I learned to study in college years ago. At the time a professor told me that if I really wanted to learn difficult subjects that I had to read everything in the text book and be able to write a sentence or two, at the very least, about every sentence in the book. I was a slow learner with learning disabilities that went back to pre-kindergarten so while many people could pick things up easily, I wasn't that type of person.
So for me, courses like organic chemistry, physiology and physics, to name a few, were difficult. It was frustrating because many of my classmates made it all seem to be so simple. Then again, most of them had already taken preliminary courses in high school.
When I picked up ISO 9001 back around 1990 I did the same thing, though. I bought copies of the standard and associated documents, wrote them out, and bought a number of books on ISO9001 (pre-internet days so I got several books from the library, too). I got to the point where while I didn't know the standard by heart well enough to recite it, I did know every sentence to the point where I could discuss each and relate each to company systems.
I will say that by typing the standard into a Word document it was also a big help to me over time - Easy to search and copy of paste from.
I also did an audit compliance document taken from the parts of the standard. ISO 9001 has changed a bit, but at one time I could discuss every sentence, its intent and how to comply.
I am sure others here will give you their take on how to do that these days, with the internet available and all that.