They are a handy set of tips to guide your evaluation in order to determine if a source is reliable, credible, and authoritative.
How do you use them?
Ask the suggested questions. How you answer them should help you determine if your source is a good one.
The 5Ws Quick Chart is your handy one-stop-shop.
For detailed explanation, check out the More on 5Ws tab (in the left-hand menu above). It provides more information about each W to help you understand the good and the bad of sources.