We want to integrate Zammad with PlentyMarkets using a TAB on ticket dashboard, so when a ticket arrives, we can call PlentyMarkets Shop using API REST and show on Zammad key information about the ticket.
You could learn about ruby & rails and add some kind of event module for zammad on the ticket creation which gathers the information and saves it to the ticket into object manager attributes.
You could host your own code which accepts zammad webhook requests. With that you would be able to be informed when a zammad ticket is created. Then you could gather all related information you want to show up in zammad and save it to object manager attributes via ticket update request.
Like: Zammad ticket create → Wehook → Your script → Your scripts calls PlentyMarkets → Your scripts updates the zammad ticket