QT Modeler, by Applied Imagery, provides a variety of tutorials on their website via their YouTube channel.
A few popular tutorials are linked below:
Article ID: 825
Created: September 4, 2015
Last Updated: September 4, 2015
Author: Marianne Okal
Online URL: https://kb.unavco.org/article/qt-modeler-beginners-039;-resources-825.html