easy!
Every movieclip, graphic object and button has it’s own timeline.
“_root” refers to the main timeline! [ The timeline that appears when you open a totally new unchanged movie ]
now make a movieclip in “_root.” (the main timeline)
Select it and change it’s instance name to “mc” (without the quotation marks “”)
now let’s say you have an animation inside that movieclip and you want to go to frame 18 of that animation. then it would be like this:
_root.mc.gotoAndStop(18);
_root <-- the main timeline
each timeline is separated by a “.”
mc <— the movieclip (remember the instance name)
gotoAndStop(18); <---- makes it go to frame 18 and play.
So if there was another movieclip with instance name “mc2” inside that movieclip and you want that one to go to frame 18 it would be like this: