From the main Instructors screen, click the Add an Instructor button, then type in a few characters to bring up a list of users (Instructors are a user that has been assigned a sub-role of Instructor). Click on the user to assign them as an instructor. 

Here are the fields available on the form — all of which are optional. Note you can click the Preview Instructor Page button to see your changes and preview the page as your users will see it.

Instructor BIO (Overview)

Add a brief (one or two line) bio about this instructor that is displayed to users who are viewing the session overview page for a session that is taught by this instructor.

Instructor BIO (Detailed)

Add a more detailed bio about this instructor that is displayed when a user is viewing this instructor's page.