BigJohn, actually that's a very good question.
First I will just pass it on what others say about universal library or Akashic records (Akash in Sanskrit means the sky). As you must be knowing, its a place in astral where all knowledge, past or future, is stored and few lucky humans have access to it. Those who need it for some greater purpose or greater good get access to it and they instantly know anything and everything about whatever it is. It mostly appears in the form of a huge library where the books are 'alive'.
Ok, so goes the traditional story about it. However I never heard about a Matrix style process, where you can download knowledge into your brain. But there are ways to gain knowledge in astral which would seem equally magical.
Note that Bruce uses the term download to mean retention of memories while waking up to normal consciousness. So don't get confused.
Now let me tell you about it from my personal experience, whatever little I had during these years. Learning and even communicating something in astral is very different, you dont need to read word by word or hear word after word or you don't need to practice to learn new skills these (for example, when I first flew in astral , I did not practice even for a second, I just did it).
When, once, someone tried to communicate something to me, it took the form of a picture book, where pictures were morphing and made little meaning to me. It seems that you need to be 'evolved' enough to get such instant knowledge and skills without painstakingly learning it all. But to get to that level you need to learn a lot here in physical, including astral projection skill and spiritual soundness and strength in general.
So its easy once you know how

As Stookie rightly said, physical is a kindergarten where you learn the basics, once you are a master in it, you have better ways to higher knowledge. But I guess, it would seem as difficult as some things are here right now.