Add chapters to a video

I need chapter timestamps added to a 12-minute tutorial titled 'Photoshop quick masks.' Insert five chapters with clear short labels and start times: 0:00 Intro, 1:05 Selection basics, 3:30 Quick mask workflow, 7:10 Refining edges, 10:00 Export tips. Ensure timestamps are in mm:ss and the list is ready to paste into the video's description.

Before I publish chapters for the tutorial, make them easier to scan on mobile and helpful to decision-makers. Bring the time to the left, shorten labels to two to three words, bold the chapter that covers the main workflow, and flag any chapter that might confuse beginners.

I pasted five chapter timestamps and viewers drop sharply after 'Selection basics' at 1:05. The video shows several quick cuts and a dense demo. I'm not sure whether the timing is wrong or the label is misleading. What is the likely diagnosis and the fastest change to test?

Across my tutorials, chapters either miss key steps or are too granular, and editors keep overwriting them. I manage a small creator team. Where are we losing viewer trust and time, and what single new convention should we adopt so chapters reliably guide returning learners?