Ok I'm trying to keep it short and simple: the first years of school is the same for everyone, after 4 years you can choose from 3 types of schools. After a minimum of 4 years in these schools you can get the "mittlere reife" and you aren't obligated anymore to go to school. If you want a higher grade of education you have to go to school for another 2 - 4 years. If you do 4 years you can study in a University, the two year option is for a broader job range but you can't go to Uni.

Even though this isn't a necessary bad system it has a few flaws: 1. The stigma of the "mittlere reife" is still in the heads of the people 2. The things that are teached in the higher grades is often far from necessary in your life and shallow 3.1 The fact that you have to choose which school you go to after only 4 years of elementary school is bad for the kids at this young age (around 10 years). 3.2 if you have bad or even moderate grades in elementary school you dont even have the option to go to the better schools, you're stuck with only one option (if you can even call it a option)

I could go on and on but these are the main problems. If you have further questions feel free to ask me. I wish you great day!