I've had mine for over a year and love it.
If you're using the stock interface, the manual should be sufficient for you to understand how it works.
If your pq came with 2.1.1 I'd advise you to get 2.06 from pocketbooks support site.
It's much more stable when online.
Getting books into it is a piece of cake. download to your cpu plug in your pq and turn it on........works like and sd card. Drag and drop books into your pq. I use an 8 gig card and put all my books on it.
From my experiance The amazon app works great, kobo not so much and forget B&N
I get most of my books from Smashwords............a lot of really good free books there.
Especially sci-fi.
There are free daily kindle books as well.
Don't forget to check out
www.the-ebook-reader.com lots of great reviews and advice.