The Trigger Instrument Editor is an application that allows the creation of TCI format files. TCI files are multi velocity, round robin, multi articulation files that can be loaded into Trigger.
If you have not installed the editor yet it you can download it here.
Trigger Instrument Editor should be an Alias that installs to your Applications folder. However if not, you can find it in this location.
If you're still having issues with Trigger Instrument Editor please reach out to support.