Tree view model is the way of showing tree with parent based category.

The content prepares like the standard content pattern. The trick is grouping item has to be added to the main field list and also content models have to inserted like below;

1 - The main ID has to be added to the list by choosing the "Merge an another main field" option.

2 - ":" text has to be added to the list by choosing the "Add a static text to the main field" option.

3 - Parent ID has to be added to the list by choosing the " "Merge an another main field" option.