The course number is to give them an idea of the level of the course (1 = freshman, 2 - sophomore, etc.) The letters before it don't matter because you designate what type of course it is in a separate place on the screen.
As Popoy mentioned, use the next block wisely in decribing your class. There is a character limit so make sure you clearly designate a course which is a lab or other non-lecture course (research, independant study, etc.)
Good luck!