hi,

see due to covid 19 pandemic many of the colleges and university are arranging online classes for students who are in the middle of the year or in any semesters. generally students are joining via live sessions in youtube or zoom app or google classroom, also it depends on your college professors or lecturer on how they would arrange the class, you may contact with the respective professor or the other class mate to help in join the class, however classes are generally restricted for only the particular college students, so if you not belongs to the same college you can not join the online sessions it it is limited for only college students.