There are basically two approaches to online courses, and you will need to determine how your professors plan to proceed.
Synchronous courses have an element – maybe a weekly video lecture, maybe a group video or chat (messenger) discussion – where you have to log in to participate at a certain time for a certain amount of time.
Asynchronous courses DO NOT require that you ‘show up’ at a certain time.
NOTE that both kinds of courses will have deadlines of some sort. For example, in my own classes this Spring 2020 semester, all course sections are asynchronous so students don’t have to ‘show up’ at any given times but there ARE deadlines for all course work that they will be expected to meet week-to-week. (When they do their work WITHIN a week is up to them.)
"Online class" does not mean "anything goes."
If you have had to transition to "all online" due to the COVID-19 pandemic, your professors should have already let you know how they are going to proceed, either by releasing a formal updated syllabus or calendar, or perhaps letting you know by email or via an announcement on Blackboard (or whatever learning system your university uses). If you have any confusion or have not heard from a professor, don’t be shy about contacting them first!
For some tips on succeeding in online classes from an actual (current) student, I recommend this video:
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