Maybe you're just getting into studying witchcraft, and all of the information is completely overwhelming, been there! Everyone has to start somewhere to get to the person they want to be, don't forget that! You may be wondering what the difference is between a book of shadows and a grimoire, basically a grimoire is a record of your magical workings, while a book of shadows can contain anything you want to study about witchcraft. My advice would be to start with a book of shadows that way you can add all of the information you feel you need to study along the way. Once you feel confident in your craft and magical practice a grimoire is where you would actually put spells that you've worked, recipes you've made, lists of herbs and spices you've grown. Though keep in mind there are no hard fast rules, so if you want to keep one book, and call it your personal journal don't let anyone stop you!
If you want help starting your book of shadows I have a ton of helpful book of shadows printable sets of pages, I recommend printing them out, 3 hole punching and putting them in a 3 ring binder that way you can flip through them, color in what you want, highlight and add your own notes, its also nice to be able to reorganize information and add extra pages whenever you feel the need.