Groups haven't changed much at all from Flash 4 to Flash 5. When selected they have a single selection indicator. And to edit them, just as in Flash 4, you simply double click. To exit group edit mode either click the scene 1 tab at the top or double click the background. The functionality of symbols remain mostly the same as they were in Flash 4.
Graphic symbols are symbols which are slaved to the main timeline.
But when it referenced on the main timeline you will have to give it enough frames to play. Remember, no buttons, frame actions, frame labels or sound inside a graphic animated symbol. The hit state is never seen by the user but rather determine the area that the button is active in all the other states. Movie clips are now the default type of symbol in Flash because most people who use Flash for interface development use almost nothing else for building their interface elements and animation. We used to access these timelines with a tell target command.