Sure.
These are all technical terms. Class 1 instructors are the top of the food chain. They are allowed to teach how to become an instructor. Class 2 instructors are basically the same as class 1, but they're not allowed to teach instructors. They have a lot of experience and they supervise junior instructors. Class 4 is the most junior instructor you will find. They usually come right out of flight school and are trained by us. Class 3 is an intermediate stage, between class 4 and class 2, where they are given a little less supervision.
When we train pilots, we need to spread our instructors over x number of pilots. We do about six students per instructor, which gives us the ability to have the resources to monitor how the training is done and to ensure quality of training. Those instructors are usually class 4 and class 3. The class 2 instructors supervise the class 3 and the class 4. Basically, the class 1 are teaching those instructors on a regular basis how to improve their performance and how to train properly, quality and safety being at the centre of everything we do.