At this time, the combat functionality in RPG in a Box is very limited. The plan is to expand the current turn-based tactical system (and to implement other combat systems) once I've completed the upgrade to Godot 3.0. I expect this to be sometime in early 2018. In the meantime, refer to the Battle Editor and Enemy Editor pages for more information about the functionality that's currently available.

Turn-based tactical is the default combat system for RPG in a Box.