The NFPA 70E standard runs more than 100 pages. Obviously, you can’t remember this much information or take the time to read it before each job or assignment. And just relying on the index might cause you to miss something important. You have to understand its arrangement.
The arrangement of NFPA 70E has similarities to the arrangement of the NEC. This is true for several reasons, not the least of which is that many of the 70E panel members are NEC experts. It makes sense to follow the familiar, and you see that in the 70E arrangement.
Some features are identical. For example, definitions are in Article 100. Following the main body, there’s a series of Informative Annexes. Article 90, the Introduction, provides a good overview of the standard including its scope and purpose. Section 90.5 explains the differences in mandatory rules, permissive rules, and explanatory material.
These similarities go a long way in helping you learn and apply both standards.