We can start by opening up Salesforce and navigating to the Customer Opportunity in which we want to "Select Info to Transfer" from the Magical panel. Point and select the info you're interested in and add a label (e.g. Opportunity Name) so you can easily remember them. Hit Done.

Next, we can create our template. Select Template tab and Create Template. Click the ellipses {...} to select the placeholder e.g. Opportunity Name to add it to your template.

Now, every time you use that template in Zendesk, your placeholder will automatically fill with the labelled information from Salesforce.