One is an article and the other is a video that breaks down creating the visual step-by-step. Both do a good job explaining how to create this particular visual and how to use the narrative expression editor. Check these out and let me know if you have any further questions!
Thank you for sending over the Arena link. I went through it and I think I created a solution to your scenario. Refer to the screenshot below on how I set up the insight narrative:
Yes you can have multiple lines within an insight narrative. All you have to do is add another ‘Block IF’ in your edit narrative block and as long as the logic is similar to what you already have, then the output will show two lines. To make it easier, you can copy one of the ‘Block IF’ and paste it right below in any of the free space. After that you can follow the same logic but replace the conversion rate to AOV.