There are two ways to add a file for students to download. You can add the file as a file, or add it as an item. We'll look at both options.
In the following screenshot, we have added two documents to the course. They are the first and second things on the page, Water Inventory Homework.rtf and Ocean Salinity. They are both .rtf or word-processing documents. The first one was added as a file, and the second as an item:
Notice that Water Inventory Homework.rtf, the one added as a file, consists of only a title. This title is the link to the file. When clicked, the link will download or open the file. Notice that Ocean Salinity, the one added as an item, consists of a title, a description, and a link to the file. In both cases, you are supplying a file to your students.
If the file requires explanation, consider adding it as an item. If the title will give your students enough information about the file, consider adding it as a file.