Task groups are the optional level of hierarchy between projects and tasks in WeTrack. They will most often appear in list form in a Project Details Page or on the Projects & Tasks Homepage.
Click on your avatar in the bottom left-hand corner of any WeTrack page and navigate to Settings > Planning > Sort Task Groups By. You can sort them alphabetically, by RAG, by number of tasks, by earliest task start date, or by earliest task due date. Alphabetical is the default.