Battle Symphony is a free and open script which provides a battle system with visual battlers and action sequences for RPG Maker VX Ace. Furthermore, this script is always up-to-date and has various add-ons for your purposes. Battle Symphony also provides its own language – Symphony Tags – to easily create action sequences, for more information, please find in Manual and Tutorial.
For Symphony Tags and Action Sequences setup, please visit Manual.
Also, there are some tutorials for Battle Symphony: