If it's cold it is hard work to get it pliable enough. It's easier to split it into small chunks and knead it, then ball it all together and give it a quick knead before you roll it out.
I personally like Covapaste for covering cakes as it's quite soft. It needs CMC or Tylose added to it before you do any kind of modelling though, because it's too floppy.
Some of the cakes in that book are quite tricky for a complete beginner, even though they say they're 'easy'. Which ones are you thinking of doing?
Carol Deacon is a good author to look out for, her cakes are as effective but a bit simpler if you're a novice, try this one for cakes for all ages/occasions.
Bella, I've got that one too, and I used to one on the front as inspiration for the blue and cream one on my profile! It's so effective but really simple.
The other book I swear by is this one. It has loads of info from quantities, to baking, to filling and covering, to decorating, modelling and adding tiers. It's a really handy reference.