Hello @maike_jockisch. There are 2 types of events. There is a conversion event and a purchase event. If you are using the e-commerce extension, when the order id is populated, the purchase event will automatically fire. If you aren't using the e-commerce extension, you must map your order id variable to Order ID in the E-Commerce section of the mapping toolbox for Facebook.
If you are wanting to fire the Conversion event:
When you go to the Facebook tag and click edit, go to the Data Mappings section.
Choose a variable that will indicate that the user has done a conversion. Now click Select Destination. This will open the mapping toolbox.
Click on the Events tab.
On the left side, enter the text of the variable that should trigger your event.
On the right side, select Conversion from the drop down list.
Click Apply and Apply again.
Save and Publish.
Test.
Now when your variable has the specified text, the Conversion event will fire to Facebook.
I hope this solves your problem.
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