All of the documentation in the Student section still applies to the GoReact app in Brightspace, the only thing that is different is where you will access the course content.
If your instructor is using Brightspace, then you cannot access your course directly at goreact.com. Instead, all you need to do is log into Brightspace, open your course, and open an assignment that uses GoReact.
Registering for GoReact
Submitting a video
To submit a video to GoReact, just open the applicable assignment in Brightspace, and click the red "Start Assignment" button to record or upload your video.