Setting up other items for sale scrollbar images at bottom of every page

[apocolyte1comics]

I am an Ebay seller who is returning after a five years hiatus - everything is different and confusing, and Ebay "help" sucks, they are cluesless.  I spent an 1 1/2 with "help" who couldn't figure out how to get my other items for sale to appear in that common scrolling images horizontal bar at bottom of Ebay auction pages.
It used to be easy, who can help me? 
How do I set up the other items scrolling images??

[ferncliff-39]

@apocolyte1comics 

Ask on the Seller Tools board -

https://community.ebay.com/t5/Seller-Tools/bd-p/tools-apps-db