The three important points about the format of CD coding I will be discussing are category, subcategory and subclassification. Everything is divided by sections to make it easier to code. The category is a three character code that represents a single condition. Subcategory is a four category code it provides more information than the three character code regarding cause, location and how the condition has progressed. Subclassification is a five to seven character code that helps by adding even more information about the condition and description of it. With all of this information it can make it easier to find the right information in the manual but it will take some time for you to get used to. 

Reference:

Carol J. Buck, Saunders (2022). Step-by-Step Medical Coding, 2022 Edition, by Carol J. Buck, Saunders