For the advanced courses (ALS, ILS, EPILS, EPALS and NLS) you first have to do a provider course and get awarded an IP (instructor potential) at the end of the course. When you have the IP, you can follow a GIC (generic instructor course). After which you become an IC (instructor candidate), as IC you have to instruct on two courses. If both are satisfactory and you are ready for upgrade, you become a full instructor.