These are all different exams. If you're in scotland you would do the national 5. If you're in wales you'd do the welsh baccalaureate (I think). It really depends on where you live in the uk. After that you can do A-levels, T-levels, BTEC, apprenticeships etc. It really depends on what you think is best for you. A-levels are quite difficult it goes on for 2 years and you sit exams at the end of 2 years. BTEC is just course work.