To integrate Fibery with Zendesk you should install Zendesk app.
Here is the video that shows the whole process:
Click New App → Start with a template. Then click Integrations and find Zendesk app. Click Sync.
Now you have to insert URL to your Zendesk account and authorize it. After that sync will start and Zendesk app will appear in the left menu section:
Now you can open Tickets and link feedback to real Features, Bugs, and Ideas.