How to group and ungroup models?

Hello, please select the models that need to be grouped in the scene or the object list on the left, then use the shortcut 'Ctrl+G' to group them, or right click on the object list and select 'Group'. 'Ctrl+Shift+G' is used to ungroup.

Please note:

Model order is the default. When adding objects, the items will be listed below the selected item(s). When grouping, objects in the group are listed in the order of selection from the object list.  When ungrouping, the elements are arranged sequentially starting from the position of the topmost element in the group and moving downward.