Move dialogue line backward

I’m implementing a linear poem and wanted to have option to go back. Probably yarn is not an option? If every line (key) has a number, image, voice and music (value) so am i looking at some sort of array? and how do I read from a file?
sorry …

If I understand what you are after correctly, I think a structure of structures will be the best variable type. Something like :

To read from a file, look under File System when you add a new action :

If you save your poem and it’s details in JSON format, you can read it into the PoemLines variable (from my example structure) in once command. Otherwise you’ll have to iterate through each line you read in and process it.