Editor/Scene Editor, if there is a + sign in front of your object's name,
it means that it is grouped. Click on the + sign to get the drop-down list
of the objects within the group. To select an object within the group,
click on its name. Now you can access and edit just that particular object. If
you want to work on the group as a whole again, just click on the name of the
whole group. Here again it helps if you named your objects, because it will be
easier to find them. When you group two or more objects together, the group will
get a default name. Right-click on the object tool to open up the Object Info
panel and give the group a unique name.
advantage of using different kinds of grouping (parent/child and siblings) is
that when you set up a hierarchy carefully, it will be easier to edit different
parts of your group in the future. For example, in the attached picture (above
right) you can see that the limbs are grouped as siblings. This means that if
you want to do the same kind of editing on all the arms and legs (e.g. to put
the same texture on all of them), you don't have to select each individual
object - you can just select "limbs", do the editing you want, and it
will be applied to all the objects within this subgroup, but not to the others.
To ungroup an item, first select it, then choose the
"Unglue" tool. Or, inside the Keyframe Editor (tS5) or Scene Editor
(tS6), select the item, right-click on it, and choose "Unglue" from
the pop-up list.