he means to just sketch out the animations before going into detail
to give the eye something it can understand, dont just make lineart-animations, but make silhouettes of shapes
something like such:
Adam means something like the 4th frame of this animation (i myself like to do everything in even smaller steps so i make stickfigures first and add in bodyparts 1 by 1)
basically, dont get lost in small things and spend time detailing before you have the animation down