Hi Smiling,
I bought this deck last year and I really approach it by intuition and looking at the images. Of all my decks I find the book pretty useless! (which is hilarious really because there is so much writing about each card). Some of the pages are the earlier deck as discussed before but also when I look at the images I really feel a disconnection between the writing and card art, even on the cards that do match! I mostly ignore what the author intended on this when I read from it.
This is my first deck in this sort of genre and it's an area I feel I have a connection with, plus it has British historical areas that I have visited myself which are cute
I didn't understand the Wheel of the Year very well which the book talks about a lot. I think as a beginner to the deck it's not vitally important but you can research and understand about it as you go, it's basically a very large spread in the book but also a pagan calendar of annual festivals and each card has a 'season' or event association to it for that purpose.
My suggestion on reading it, is to look at the cards and make your own interpretations first and then look it up in the book. I find I largely ignore what the author intended and go with my own take! However the historical meaning in the book is useful, explain about Avalon or Arthur or what this bird means etc. If you get stuck search google for more historical background or look up the symbols that way. There is also a study group for it on AT
here. Sadly it looks like the study group never completed every card and it's not easy to find the study group links, so bookmark that link for the index of cards that are discussed. It has helped me in the past.
I think Nisaba is right, scrying or reading the cards intuitively really has given me excellent readings with it so far
I have found a little background or history to the card themes does help though, what was the basis of the legend in this card? sort of idea! Oh one final thing, try to ignore learnt tarot meanings and RWS meanings, this deck is so different I think it's very difficult (and confusing) to apply "generic RWS meanings" to it. Read the cards as they are, try not to compare them to the usual card equivalent. Enjoy getting to know them Smiling