Now we will discuss a few details of how to run the simulator. First you must start it. Then you load a source file written in CSC-1 assembler language. This file's name must always end with the extension .as When you load the assembler file, the software automatically assembles it into machine code and checks for errors. This phase writes a file whose extension is .o (for output of the assembler phase.)

Then you will run it by pressing buttons. You can run the program until it finishes by pressing the RUN button, or you can run only the next line of machine code by pressing 1 step. If you press the RUN button, you can interrupt it to regain control or stop a runaway program.