Uploading a copy of your class presentations or class notes prior to class provides students with a mental scaffold on which to build their reduces the extraneous cognitive load caused when the learner has to both process your meaning, combine it with their existing knowledge complete notes all at the same time. You may also have supplemental materials, references or graphics you wish to share with the students in your course as files rather than typing it all into your course page will keep your course page clean and uncluttered.