You should add a small contribution to an article related to this class, or add a citation to a claim that doesn't have one.
Complete the "Sources and Citations" training.
When you make a small claim, clearly state the fact in your own words, and then cite the source where you found the information.
The Citation Hunt tool can show you some statements that don't have citations. You can use that to find an article to reference.
First, evaluate whether the statement in question is true! An uncited statement could just be lacking a reference or it could be inaccurate or misleading. Reliable sources on the subject will help you choose whether to add it or correct the statement.