<slight overall plot spoiler Very high level>
the book is just about the same
the show has so far been very true to the book.
heck even the cut scenes over to the other storylines feels like it matches the book exactly.
The dialog too.
The first book is over 1000 pages, so you can imagine it takes time to build up a whole story.
But where's the overview to follow along.
There's 1 overall story line, 3 main story lines- with 2 that spawn off it, and 2 side stories that have been revealed in the show so far.
The overall is that everyone is fighting for the iron throne.
3 major story lines where everything spawns off are:
with 2 side plots that spawn off it
There's also 3 side stories that sneak in there but really ins't part of hte major story line but will form significant side stories.
Jon snow and the night watch
and another 2 other fun little plots that I won't spoil as the show hasn't gotten there yet.