UML Class diagrams


 * Association describes the relationship between two or more components
 * Multiplicity describes the number of elements possible in a relationship between the components
 * One to many
 * Many to one
 * One to one
 * etc
 * 2, 4 indicates 2 or 4
 * 2... 4 indicates 2-4
 * Navigability describes the directional flow of data in the association

Operations
Operations describe what instances of a class can do


 * Getters and setters
 * Perform calculations
 * Send messages to other objects
 * Create or destroy links

Use https://en.wikipedia.org/wiki/Class-responsibility-collaboration_card