In your assignments, you will be asked to use sources that are both credible and relevant. While there are some tips to help you gauge the credibility of a particular source, relevance is something that you will be expected to judge on your own based on the source content and your intended purpose for it. Relevant sources should be appropriate and strongly connected to your arguments.
Check the following video created by the North Carolina State University Libraries to learn more about credible sources:
Applying the "CRAAP" test to your sources can help you decide if they are credible or relevant enough for your purposes. Check the image below for a description of the "CRAAP" test: