Hi Frederick,

re:
> How do you add a new object to an existing group?

Select the object and then click on the group name in the "Objects" section of the scene browser.


> How do you remove an existing object from a group

Select the existing object and use either Ungroup to move it out of its current group and up one level in the hierarchy, or use UngroupAll to completely remove it from the entire hierarchy in one shot.


> or move it to another group?

Select the object and then click on the group name in the "Objects" section of the scene browser.

- Michael