If you haven't already, I recomend reading the site rules and the complete list of FAQs, then proceed to the Newbie Central. Depending on your interests and what kind of path you want to follow, different subjects will be your calling and from there you have to do your own research and asking people that appear to be knowledgeable in that particular practice/subject that can help you. However, before you just jump right into anything, I also suggest you would benefit from starting off by learning at least how to meditate, as that skill is the basic foundation for every practice, despite which path you follow. I hope this helps a little bit :)
If you go to the forums, there is a search bar, and you should research the following : Meditation, grounding, centering, visualization and energy manipulation. These are the "basics" but they are not set in stone. Others will tell you there are more basics or less. But typically, newbies are told to begin their journey there.
Also look into all brances of Paganism. There is not just one. There a lots. Research and read up on them and see which one feels "right" to you. Usually people read about one path and figure out "Yeah, this is right for me." And then they continue studying that path.
Also, paths are very personal, and traditions are personal too. They vary from witch to witch.
I study hedge-witchery but no hedge witch is a like. It all depends on the person.
The Book of Shadows, The Grimiour, The Journal,..etc is made of the practitioner's knowledge thoughts, important dates, spells, articles, ..etc. it's pretty much what the owners use for it is, there are some people that have multiple books, this is because they categorize more, as in one book for "Articles", another for "Spells", or another for "Other important facts".
It's not really something we can tell you to do, it's more how you view what you want to do with you Book of Shadows.