What is Timing & Spacing?
Timing is how long something take to happen. If all four of these spheres take 24 frames (or 1 second) then their timing is exactly the same.
Spacing gives the appearance of something moving faster or slower. If an object is placed closer to where your last keyframe was located then your object will move slower. If your spacing is much farther from the previous keyframe then your object will move faster.
What is Ease In & Ease Out?
Ease In is when your object starts out slower and eases into a quicker movement.
Ease Out is when your object starts out faster and then eases into a slower movement.