Papers are the individual academic components of your entire "course" for a particular semester or year.
Each paper is identified by a seven-character code. The first four characters are letters which denote the subject area (e.g. ACCT for Accounting, PHSE for Physical Education) followed by three numbers (beginning with 1 for 100-level papers, 2 for 200-level papers, and so on, e.g. ACCT 101, PHSE 235).
Each paper has an associated number of points which contribute to the total that you need for your qualification. Most papers at 100-, 200-, and 300-level are worth 18 points, but some have differing point values depending on the workload required.