You didn't include much to go on here. Screen shots are usually helpful. Are you in face select mode? Do you only have the one face selected (highlighted with a yellow border)? Have you tried Alt-E selecting the Individual Faces option?
thank you for replying! I mean, like 2:30 in the video, the extruded meshes should move individually when I extrude it individually. but even though I clicked 'extrude individual' and try to move one of them, they still move together as though it's still cohesive. :)
