- Vocational: 2 or 3 years followed by 2+ years as an apprentice in a real company, often with a master craftsman where the apprentices pay increases from approx 30% of full pay and up towards full pay during the time you stay. In return for the limited pay they have to take time to teach you and they cannot easily let you go before your apprenticeship has ended.

- Study preparations: three years of languages (typically the two Norwegian ones, English and German but some people will choose French or Spanish or something instead of or in addition to German.) Students who aim for engineering or medicine studies will typically add math, physics and another sciency subject: chemistry and biology were popular back when I went to school.

- leave school and get a job (or more and more likely it seems: fall behind)

As for why I say roughly, there's been a very nice option where you could get certified as a craftsman and get enough subjects to enter engineering in four years.

Also there are some options for transitioning from vocational to other studies. Going the other way is pretty hard and probably involves getting a job as uncertified worker in the field, then work for 5 years, takes some courses and pass the certification test.

Note: I'm not saying this is unique. It would surprise me if something like this isn't common in many other countries.

Lots of Americans do learn a trade in high school. Just to copy the "Programs" menu from the Tech Center at the high school where my wife teaches (suburb in VT): Automotive Technology, Building Technology, Cosmetology, Computer Systems Technology, Computer Animation & Web Design, Dental Assisting, Design and Creative Media, Childhood Education & Human Services, Engineering & Architectural Design, Natural Resources, Professional Foods, Health Informatics. I understand that many of these programs, if not all, are supposed to be a career for the students, and that many of them are thought of as hard.