Like all other projects that we made in previous chapters, you can change timing and motion using the Dope Sheet window. Although you can use the window to resize and set animation timing by spacing keyframes, you should take extra care with any edits.
Since we are using a synchronized motion for each element in our project, you should make group changes by selecting only a few objects at the time.
How do you do that? Open the Dope Sheet window and, using the selection tools in Blender, isolate just a few keyframes. For instance, you can use the Alt+ A key to remove all keyframes from a selection. And select only the objects you wish to adjust the animation for.
With the B key, you can draw a box around only ...
