YouTube has a great feature called Video Chapters that allows creators to break up their videos into named chapters:
Chapters can even be added to videos you’ve already uploaded. Here’s an example where Video Chapters were recently added to an already published video.
The easiest way to get these chapters is to add orange chapter markers in Final Cut Pro, or add Sequence Markers to your Premiere Pro sequence. Then use Creator’s Best Friend to make a list of timestamps and chapter titles for you.