If you've ever tried to learn a foreign language with a different alphabet, you'll know it's no easy task. You have to re-wire your brain to recognize foreign characters and connect them to the alphabet you've been using your whole life. But the Theban Alphabet is crucial for any witch and her Book of Shadows.
The Theban Alphabet first made appearances around the 16th Century and is named after Honorius of Thebes (a mythical character from the Middle Ages).
As it's modeled after the old Latin Alphabet J, U, and W are not represented and pull from surrounding letters--meaning that any translations must interpret which character best suits the word.
Witches use the Theban Alphabet to code their Book of Shadows so that it cannot be read by any non-witches. And nothing will teach you the characters better than using them as often as possible.
I recommend starting slowly and keeping a key in your book to refer back to when needed. And one day, you won't need it at all!