Each Use Case has only one basic course. The basic (or main) course is the sequence of steps that the Role or Aactor is likely to take in order to accomplish the goal of the Use Case. The first step describes the action that initiates the Use Case.

Each step can optionally have alternate course(s), exception course(s), and/or postconditions. The postconditions of the last step is not necessary because the postcondition of the Use Case (validates that the Use Case goal was met) should be valid.

Steps can optionally refer to other Use Cases for "use relationships" or Collaboration Cases for traceability. Alternate and exception courses should be defined within the same Use Case.