Why complicated? Also we have many claims for Kabbalah that is complicated but it is not. I will say contrary: both Enochian system and Kabbalah are simple. But if you want primer of really complex and heavy text with out of measure complications please check out this book Lucifer: Princeps.
Surely this new book from preview seems interesting and I would recommend it. From older titles classics: Enochian World of Aleister Crowley, Vision Magick from Duquette and For Beginners by Donald Tyson will be enough for some time. I mean basic system is easy to understand, you have classic pyramidal structure and you learn the names or read them. What could be more complex is making of material tools but that is also easy.