The guide is a supplementary reference on Examitect's ExAC study plan, but that doesn't mean you can skip it. Section 3 tests your knowledge of sustainable design principles, and the vocabulary this guide teaches shows up directly in how those questions are written and framed.
Category 13.3 (Apply sustainable architectural design strategies) is where the guide is most relevant. If you can't name the seven LEED credit categories and explain what each one addresses, or distinguish a prerequisite from a credit, you're working with a gap. The guide closes that gap faster than any other single source because it's written for conceptual literacy, not code compliance.
The guide also introduces three ideas the ExAC tests repeatedly: systems thinking, the life-cycle approach, and the integrative design process. Read Sections 2 and 3 carefully before moving into Section 4's credit category strategies.