Make the menu "first play." (Select in project panel, right click, "first play.")
Show me the screenshot. (Edit: of the flowchart.)
I don't know what you did wrong before, so I want to see what we have.
Do you want a play all? (that is the button that links to the timeline)
For the chapters, do you want to return to the menu after a chapter plays, or does it continue on with the next chapter?