Free Jira Tutorials for Users
Atlassian University offers a variety of short tutorials for Jira. They're grouped into series, based on content theme, and each tutorial lasts anywhere from 3 to 12 minutes, so you can dive in and learn quickly. You can access some of the tutorials right from this site, or you can purchase the larger library as an annual subscription either from this site, or if you're a Cloud customer, you can purchase the entire library; as a Jira Add-on through the Marketplace.
Here's the collection of series we offer today. (Include each one with a mini-descriptions and have it link to the appropriate URL)