The lesson system
How your 12 hours are used depends on the wind. There are only two students on each instructor and each hour is very effective. You normally do two sessions of 1-2 hours each day. You need a rest with food and water in between the lessons 😉 They are intense, and you are going to learn a lot each time you are on the water. The students can expect to finish the lessons after 3 or 4 days, and you have the option to rent gear if you are independent and the instructor consider this to be safe. If you are on a different level than the other students (or if there is only one student per instructor), then you get private lessons. Each lesson is 1 hour, and you have 6 lessons in total.
What goal is realistic to have after 12 hours of kite lessons? (The summer camps)
This depends on each student, but normally you should know the safety and theory to continue practicing on your own. You have kited your first meters on the board. Some of you are already riding back and forward; some are practicing to ride upwind, while others might need a few more lessons to be independent enough to continue on their own. This is very individual.
Can I use the kite gear when there are no lessons?
No, kite gear is only included during the lessons. You can rent gear after you are done with your hours, and continue practicing by your own. Your instructor needs to approve that this is safe and ok. If you are not independent enough yet to be practicing by yourself, you have the option to buy more private lessons.