This is certainly a tough one and I cracked it. The problem here is that we are confusing learning the tool and learning the material. Appendix A is the answer, yes, but we can do better to provide clues to the resolution.
I say this because I suspect many people may have done very well understanding material and actually KNOW what they need to do but can't quite implement it. Again knowing the tool vs. knowing what to do.
So I conclude, study A.5.3 VERY CLOSELY.
Appendix A:
http://www.nand2tetris.org/chapters/appendix%20A.pdf