This is an open-source version of "Incident Response Training", PagerDuty's training course for incident response and incident command. It is based upon the course used internally at PagerDuty to train new Incident Commanders.
It includes lots of introductory information on PagerDuty's process, and details on the Incident Commander role specifically. All the information is already available as part of the open-source PagerDuty Incident Response documentation (https://response.pagerduty.com), this is just a different way of presenting it that's hopefully more engaging.
Full notes and details are available at https://response.pagerduty.com/training/courses/incident_response/