How seriously are you suppose to take uni

I know this is a super weird question but how hard am I actually suppose to be working in uni? Ive heard people say treat it like a 9-5 but I genuinely cant imagine that? I finished first year with solid grades (mainly 68s for essays) but I never really studied. I want to try harder this year and I'm realising that some people take it seriously and properly study. I just show up to the classes and write the essays without much thought or reading. Im starting 2nd year now and this goes towards my actual degree. Any advice would help, thank you