To direct the activity of an Actor during an animation requires the use of timelines and keyframes. The Keyframer is a module where the timelines and keyframes of all Actors can be viewed and edited in one display. Normally timelines and keyframes are created implicitly as Actors are added and the tools are used to move then into position and tell them what to do.
In the keyframer window time runs in the horizontal direction and for each Actor the extent of timelines and position of keyframes is displayed.
The timelines are the red horizontal lines and the colored dots at the end of the timelines are the keyframes.