If you want to write your own custom business logic on server in AppWarp.You need to use AppWarpS2 where you can override existing AppWarp functionality and write own game busniess logic. You can go through with AppWarpS2 API Documentation.
You can write own game logic either of following based on requirements.
Using Room RPC : You can define your own function on server side at RoomAdapter and call this form client side using invokeRoomRPC API
By overriding handleMoveRequest : You can also override it you using sendMove from client side.
Let me know if more queries are concern.