In your code create an AR.Tracker and load the target collection file from the previous step
Create an AR.Trackable2DObject and assign your targetName
Make sure that the targetName used with the AR.Trackable2DObject correspond to one of the target names in your target collection. You can also use a wildcard to match any target or only a specific subset of targets. Please refer to the AR.Trackable2DObject main documentation for more information about wildcards.
Should the problem persist, please provide us with the needed code snippets of the initalization of the Tracker and Trackable2DObjects and the .wtc file, so we can check on our end.