For the first part of your project (if you have not already completed it), I suggest looking at the “Example Scripts” section of the Maestro Servo Controller User’s Guide. You can find various script examples, particularly the “Using a button or switch to control servos” sub-section, that can help you get started.
The second half of your project would be difficult to implement since the Maestro does not support interrupts on its inputs. You could use a separate microcontroller to detect the button push and send the "Restart Script at Subroutine " or “Stop Script” serial command to stop the current script. Alternatively, depending on the behavior you want and your setup, you could connect button B to the reset pin on the Maestro board. If you want your animated object to return to some default position after resetting the Maestro board, you can set the default positions for each channel under the “Channel Settings” tab in the Maestro Control Center and select “On startup: Goto” as the startup behavior.
If you run into problems while writing the script, please post what you have so far along with a more detailed explanation of how you want the script to work, and we might be able to offer additional suggestions.