Editing Keyframes in the Active Viewport To quickly set up an animation, position your layers to set keyframes in the active viewport. To edit a keyframe in the active viewport: Click or in the playback controls to go to the previous or next keyframe. The next or previous frame that contains a keyframe appears in the active viewport. Edit any of the layer's Transformation channels. The keyframe automatically reflects any changes you make.
To quickly set up an animation, position your layers to set keyframes in the active viewport.
The next or previous frame that contains a keyframe appears in the active viewport.
The keyframe automatically reflects any changes you make.
or 
in the playback controls to go to the previous or next keyframe.